Is there a documentation about reading mode in firefox ?

I don't think there is any good documentation. I suspect it is a mix of under-development [WiP], experimental, and potentially being deprecated in favour of Pocket, at least in some locales|builds. Note the feature differs on Android & there may be an increasing number of users on Android. I don't think there is any proper developer guide but there are a variety of places to look for information, some may appear at a later date : * End users KB ** [https://support.mozilla.org/en-US/search/advanced?q=Reader&language=en-US&category=10&category=20&sortby_documents=relevance&a=1&w=1#kb Search] ** e.g. [[Firefox Reader View for clutter-free web pages]] {pocket) <br /> [[View articles in Reader View on Firefox for Android]] * Bugzilla e.g. (Please note [https://bugzilla.mozilla.org/page.cgi?id=etiquette.html etiquette]) ** Bug 1157197 - Please enable reader view for 38.0.5 ** Bug 1163434 - Provide other read it later services than Pocket {rfe) ** Bug 1155467 - (Pocket) [meta] Firefox Pocket integration {Pocket is the default reader list for 50% of Firefox worldwide) * [https://wiki.mozilla.org/index.php?title=Special%3ASearch&profile=default&search=pocket&fulltext=Search wiki.mozilla] {often has docs on features * [https://developer.mozilla.org MDN] [https://developer.mozilla.org search] (The search was ''improved'' recently You may want to also try external searches [https://www.google.co.uk/search?client=ubuntu&channel=fs&q=%22Reader+List%22+site%3Adeveloper.mozilla.org e.g.] ) * Release Notes etc. [https://developer.mozilla.org/Firefox/Releases MDN], [https://www.mozilla.org/en-US/firefox/releases mozilla.org] -> '''[https://www.mozilla.org/en-US/firefox/38.0.5/releasenotes/38.0.5 38.0.5] {mentions Pocket) ''' * '''[http://mxr.mozilla.org/ MXR]''' Note coding cross references [http://mxr.mozilla.org/mozilla-release/source/browser/components/pocket/ e.g.] '''You would be better asking in the developers forum'''. If you do so please post back here to cross link the developers answers * [https://www.mozilla.org/en-US/about/forums/ Forums] ** [https://www.mozilla.org/en-US/about/forums/#firefox-dev #firefox-dev] There may be a better forum to use but ask over there.