About your important data and their files

Check out the table below to understand your Firefox data within your [[Profiles - Where Firefox stores your bookmarks, passwords and other user data|profile]], what it means, and where you can read more information. {note}'''Note:''' This is not a complete list. It contains files you may wish to back up or [[Restore bookmarks, passwords, and data from an old Firefox profile|restore from another profile]].{/note} <!-- If file names are updated for a new Firefox version, also review the https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data#w_what-information-is-stored-in-my-profile and update, if necessary. --> {| !File !File type !Definition !More details |- |places.sqlite |Bookmarks, downloads, and browsing history |It contains all your Firefox bookmarks and lists of files you have downloaded and of websites you have previously visited. |[[Bookmarks in Firefox]] |- |favicons.sqlite |Bookmarks, downloads, and browsing history |It stores website favicon images. Use it when recovering the places.sqlite file. |[[Bookmarks in Firefox]] |- |key4.db |Passwords |It stores your key database for your passwords. To transfer saved passwords, you must copy this file along with the following file. |[[Password Manager - Remember, delete and edit logins and passwords in Firefox]] |- |logins.json |Passwords |Encrypted information about your saved usernames and passwords. |[[Password Manager - Remember, delete and edit logins and passwords in Firefox]] |- |permissions.sqlite |Site-specific preferences |It stores many of your Firefox permissions that are decided on a per-site basis. For example, it stores which sites are allowed to, or blocked from, setting cookies, installing extensions, displaying popups, etc. |[[Site Permissions panel|Site permissions]] |- |search.json.mozlz4 |Search engines |It stores user-installed search engines. |[[Add or remove a search engine in Firefox]] |- |persdict.dat |Personal dictionary |It stores any custom words you have added to Firefox's dictionary. If you have never added a custom word to the Firefox dictionary, then you will not have this file. |[[How do I use the Firefox spell checker?]] |- |formhistory.sqlite |Autocomplete history |It remembers what you have searched for in the Firefox search bar and what information you have entered into forms on websites. |[[Control whether Firefox automatically fills in forms]] |- |cookies.sqlite |Cookies |Cookies are used by websites for a variety of reasons, some of which include keeping you logged in to a website you have previously logged in to, remembering any preferences a website has allowed you to set, authenticating you as a person who has visited a specific website before, etc. |[[Cookies]] |- |cert9.db |Security certificate settings |It stores all your security certificate settings and any secure website certificates you have imported into Firefox. |[[Secure website certificate]] |- |handlers.json |File types and download actions |It stores your preferences with respect to what Firefox does when it comes across known file types, such as whether you want to save a file or open it with a specific application. |[[Manage file types and download actions in Firefox]] |} ''Based on information from [http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox Transferring data to a new profile - Firefox (mozillaZine KB)]''

Check out the table below to understand your Firefox data within your profile, what it means, and where you can read more information.

File	File type	Definition	More details
places.sqlite	Bookmarks, downloads, and browsing history	It contains all your Firefox bookmarks and lists of files you have downloaded and of websites you have previously visited.	Bookmarks in Firefox
favicons.sqlite	Bookmarks, downloads, and browsing history	It stores website favicon images. Use it when recovering the places.sqlite file.	Bookmarks in Firefox
key4.db	Passwords	It stores your key database for your passwords. To transfer saved passwords, you must copy this file along with the following file.	Password Manager - Remember, delete and edit logins and passwords in Firefox
logins.json	Passwords	Encrypted information about your saved usernames and passwords.	Password Manager - Remember, delete and edit logins and passwords in Firefox
permissions.sqlite	Site-specific preferences	It stores many of your Firefox permissions that are decided on a per-site basis. For example, it stores which sites are allowed to, or blocked from, setting cookies, installing extensions, displaying popups, etc.	Site permissions
search.json.mozlz4	Search engines	It stores user-installed search engines.	Add or remove a search engine in Firefox
persdict.dat	Personal dictionary	It stores any custom words you have added to Firefox's dictionary. If you have never added a custom word to the Firefox dictionary, then you will not have this file.	How do I use the Firefox spell checker?
formhistory.sqlite	Autocomplete history	It remembers what you have searched for in the Firefox search bar and what information you have entered into forms on websites.	Control whether Firefox automatically fills in forms
cookies.sqlite	Cookies	Cookies are used by websites for a variety of reasons, some of which include keeping you logged in to a website you have previously logged in to, remembering any preferences a website has allowed you to set, authenticating you as a person who has visited a specific website before, etc.	Cookies - Information that websites store on your computer
cert9.db	Security certificate settings	It stores all your security certificate settings and any secure website certificates you have imported into Firefox.	Secure website certificate
handlers.json	File types and download actions	It stores your preferences with respect to what Firefox does when it comes across known file types, such as whether you want to save a file or open it with a specific application.	Manage file types and download actions in Firefox

Based on information from Transferring data to a new profile - Firefox (mozillaZine KB)