The default window size is whatever you choose it to be. When the browser is closed, it should remember the size of the window and where it was on your screen.

You missunderstand. I don't choose it to be anything. I want to use the stock settings that firefox has when ther browser is first started. So what is the default/stock size of firefox?

So anyone knows the default window size firefox uses?

Here the default is 1000.

Are you currently using "Resist Fingerprinting" as your user agent shows Firefox 91.0 ?

Using "Resist Fingerprinting" normally rounds the screen dimensions to the nearest 200x100.

• https://searchfox.org/mozilla-release/source/dom/base/nsContentUtils.cpp#line-2305

If you dont mind, i am interested in both default values, with and without resist fingerprinting.

To explain why i want to know this value: I used the built in tool from windows called snipping tool to take a "screenshot" from my browser to figure out what size it is using, however the result might not be 100% accurate. I dont trust mozilla anymore since rumors say around 70% of their income is from google which is clearly hostile to privacy. Sorry to say but i lost trust in mozilla because of the big partnership with google. Firefox as it is now is not 100% open source, so who knows what's in the x% that are closed source. Anyways back to topic, i was searching for alternative browser and found waterfox which was looking good at first but then i noticed it has very bad performance and also it was acquired by an adversting company -system1. A privacy browser owned by an AD company, common seriously? So not an option. The next browser in line which seems to be good is actually a fork of firefox, = Librewolf.

When i checked Librewolf i found that they are using their own firefox.cfg Librewolf has little worse performance than firefox so i decided to experimente and take the cfg from librewolf than paste it into the original firefox. Functionallity appears to be 100% still. Expect that i had to remove the resist fingerprinting part because firefox was using other window size than normally. So when i took that screenshot from firefox without the custom cfg i got this: defaultPref("privacy.window.maxInnerWidth", 1284); defaultPref("privacy.window.maxInnerHeight", 1064); Now im worried those results are not 100% accurate and therefore if websites read my browser size i will already be different from every single user that has the default window size, which results in me being way more unique.

Maybe i missunderstand but 200x100 pixels appears to be way to smal?

Just in case it is needed i will share the librewolf cfg here:

defaultPref("librewolf.cfg.version", "5.4");

// ------------------------------- // # SANITIZING, TP, SESSIONS // -------------------------------

/**

strict mode includes:
- dFPI for both normal and private browsing
- strict blocking lists for trackers, including crypto, fping and socialtracking
- shims to avoid breakage caused by blocking lists
- stricter policies for xorigin referrers
- cookie cleaning mechanism specific to dFPI

• /

pref("browser.contentblocking.category", "strict");

defaultPref("network.cookie.cookieBehavior", 5); // dFPI is default for strict mode, but enforce defaultPref("network.cookie.lifetimePolicy", 2); // keep cookies until end of the session, then clear defaultPref("privacy.partition.serviceWorkers", true); // isolate service workers

// make third party and http cookies session-only defaultPref("network.cookie.thirdparty.sessionOnly", true); defaultPref("network.cookie.thirdparty.nonsecureSessionOnly", true);

/**

this way of sanitizing cookies would override the exceptions set by the users and just delete everything,
we disable it but cookies and site data are still cleared per session unless exceptions are set.
all the cleaning prefs true by default except for siteSetting and offlineApps, which is what we want.

• /

defaultPref("privacy.clearOnShutdown.cookies", false); defaultPref("privacy.sanitize.sanitizeOnShutdown", true); defaultPref("privacy.sanitize.timeSpan", 0);

// disable browsing, search and form history defaultPref("places.history.enabled", false); defaultPref("browser.formfill.enable", false);

// prevent websites from storing session data like cookies and forms, increase time between session saves defaultPref("browser.sessionstore.privacy_level", 2); defaultPref("browser.sessionstore.interval", 60000);

// ----------------- // QUERY STRIPPING // -----------------

/**

* enable query stripping and set the strip list.
* currently we use the same one that brave uses:
* https://github.com/brave/brave-core/blob/f337a47cf84211807035581a9f609853752a32fb/browser/net/brave_site_hacks_network_delegate_helper.cc#L29
*/ 

defaultPref("privacy.query_stripping.enabled", true); defaultPref("privacy.query_stripping.strip_list", "__hsfp __hssc __hstc __s _hsenc _openstat dclid fbclid gbraid gclid hsCtaTracking igshid mc_eid ml_subscriber ml_subscriber_hash msclkid oly_anon_id oly_enc_id rb_clickid s_cid twclid vero_conv vero_id wbraid wickedid yclid");

/**

* librewolf specific pref that allows to include the query stripping lists in uBO by default.
* the asset file is fetched every 7 days.
*/

defaultPref("librewolf.uBO.assetsBootstrapLocation", "https://gitlab.com/librewolf-community/browser/source/-/raw/main/assets/uBOAssets.json");

// ---------------------- // # NETWORKING // ----------------------

// https and mixed content defaultPref("dom.security.https_only_mode", true); // only allow https in all windows, including private browsing defaultPref("network.auth.subresource-http-auth-allow", 1); // stop cross-origin resources from using HTTP authentication defaultPref("security.insecure_connection_text.enabled", true); // display http websites as insecure in the ui defaultPref("security.mixed_content.block_display_content", true); // block insecure passive content

defaultPref("network.dns.disableIPv6", true); // disable ipv6

// always send xorigin referer but trim them defaultPref("network.http.referer.XOriginPolicy", 0); // default, might be worth changing to 2 defaultPref("network.http.referer.XOriginTrimmingPolicy", 2); // trim referer to only send scheme, host and port

defaultPref("network.file.disable_unc_paths", true); // hidden, disable using uniform naming convention defaultPref("network.IDN_show_punycode", true); // use punycode in idn to prevent spoofing

// proxy defaultPref("network.proxy.socks_remote_dns", true); // forces dns query through the proxy when using one defaultPref("network.gio.supported-protocols", ""); // disable gio as it could bypass proxy

// doh defaultPref("network.trr.confirmationNS", "skip"); // skip undesired doh test connection /**

0 = default
1 = browser picks faster
2 = DoH with system dns fallback
3 = DoH without fallback
5 = DoH is off, default currently

below prefs must be applied with pref in order to work

• /

// pref("network.trr.mode", 2); // pref("network.trr.uri", "https://dns.quad9.net/dns-query");

// prefetching defaultPref("network.dns.disablePrefetch", true); // disable dns prefetching lockPref("network.predictor.enabled", false); // disable predictor lockPref("network.prefetch-next", false); // disable link prefetching lockPref("network.http.speculative-parallel-limit", 0); // disable prefetching on mouse over

defaultPref("network.manage-offline-status", false); // let user control the offline behavior

// ------------ // # DOM // ------------

// pop-ups and window related preferences defaultPref("dom.disable_beforeunload", true); // disable "confirm you want to leave" pop-ups on close defaultPref("dom.disable_open_during_load", true); // block pop-ups windows defaultPref("dom.popup_allowed_events", "click dblclick mousedown pointerdown"); // limit events that cause pop-ups defaultPref("dom.disable_window_move_resize", true); // block scripts from resizing windows defaultPref("browser.link.open_newwindow", 3); // open 'new windows' targeted links in 'new tab' defaultPref("browser.link.open_newwindow.restriction", 0); // ignore the size when applying the above pref

// -------------------------------- // # CACHE AND TEMPORARY FILES // --------------------------------

defaultPref("browser.cache.disk.enable", false); // disable disk cache defaultPref("browser.privatebrowsing.forceMediaMemoryCache", true); // block media cache from writing to disk in pb mode defaultPref("media.memory_cache_max_size", 65536); // increase max cache size to avoid playback issues caused by above setting

defaultPref("browser.shell.shortcutFavicons", false); // disable shortcut favicons from being stored in profile defaultPref("browser.helperApps.deleteTempFileOnExit", true); // delete temporary files opened with external apps defaultPref("browser.pagethumbnails.capturing_disabled", true); // disable page thumbnails capturing

// ---------------------- // # MEDIA // ----------------------

/**

* limit potential private IP leaks for webrtc users.
* mDNS protects the value on linux, osx and win10+.
* these prefs protect the value when allowing mic and camera access, and for win7/8.x.
* */

defaultPref("media.peerconnection.ice.no_host", true); // don't use any private IPs for ICE candidate defaultPref("media.peerconnection.ice.default_address_only", true); // use a single interface for ICE candidates, the vpn one when a vpn is used defaultPref("media.peerconnection.ice.proxy_only_if_behind_proxy", true); // force webrtc inside proxy, when one is used

// autoplay defaultPref("media.autoplay.blocking_policy", 2); // only allow to play when a certain element is clicked defaultPref("media.autoplay.default", 5); // personal preference, currently apply blocking policy to all autplay including muted

// -------------------------------------- // # FINGERPRINTING // --------------------------------------

defaultPref("privacy.resistFingerprinting", true); // master switch

// rfp compatibility settings defaultPref("privacy.resistFingerprinting.block_mozAddonManager", true); // prevents rfp from breaking AMO defaultPref("browser.startup.blankWindow", false); // if set to true it breaks RFP windows resizing defaultPref("browser.display.use_system_colors", false); // default but enforced due to RFP

defaultPref("privacy.resistFingerprinting.letterboxing", false); // expose hidden letterboxing pref, but do not enable by default

/**

* increase the size of new RFP windows for better usability, while still using a rounded value.
* if the screen resolution is lower it will stretch to the biggest possible rounded value.
* */

defaultPref("privacy.window.maxInnerWidth", 1284); defaultPref("privacy.window.maxInnerHeight", 1064);

defaultPref("webgl.disabled", true); // master switch, disable webgl

// -------------------------------- // # SECURITY // --------------------------------

defaultPref("fission.autostart", true); // enable fission by default

// certificates defaultPref("security.cert_pinning.enforcement_level", 2); // enable strict public key pinning defaultPref("security.pki.sha1_enforcement_level", 1); // disable sha-1 certificates defaultPref("security.OCSP.enabled", 0); // disable ocsp fetching

// crl with no ocsp fallback defaultPref("security.remote_settings.crlite_filters.enabled", true); defaultPref("security.pki.crlite_mode", 2);

// safe negotiation defaultPref("security.ssl.require_safe_negotiation", true); // block websites that do not support safe negotiation, occasional breakage defaultPref("security.ssl.treat_unsafe_negotiation_as_broken", true); // show warning when safe negotiation is not enable and website is accessed

// tls behavior lockPref("security.tls.enable_0rtt_data", false); // disable 0 round trip time to improve tls 1.3 security defaultPref("security.tls.version.enable-deprecated", false); // default but helps resetting the preference defaultPref("browser.ssl_override_behavior", 1); // prepopulate url on ssl warning screens defaultPref("browser.xul.error_pages.expert_bad_cert", true); // advanced ui infos for broken connections

// permissions lockPref("permissions.delegation.enabled", false); // force permission request to show the real origin lockPref("permissions.manager.defaultsUrl", ""); // revoke special permissions from some mozilla

The 200x100 is not about the actual size, but is used to round the dimensions. So 1284x1064 => 1200x1000 rounded, so everybody within this range would get these 1200x1000 dimensions if I understand correctly.