Change #1251340 had a related patch set uploaded (by Aude; author: Aude):

[mediawiki/extensions/ReadingLists@master] Check only ReadingLists beta feature preference when the beta feature is available

https://gerrit.wikimedia.org/r/1251340

Change #1251340 merged by jenkins-bot:

[mediawiki/extensions/ReadingLists@master] Check only ReadingLists beta feature preference when the beta feature is available

https://gerrit.wikimedia.org/r/1251340

This can be tested by having the hidden preference set and be opted into the experiment (e.g. via the browser console)

At the same time, also enable the beta feature.

Then turn off the beta feature and this should take precedent over being in the experiment (e.g the user decided they don't want reading lists)

@Etonkovidova let us know if you need any help.

In T419990#11774785, @Jdlrobson-WMF wrote:

@Etonkovidova let us know if you need any help.

I checked on testwiki wmf.22 - and all seems to be working as expected:

• new accounts get beta features (was checked for T419163: Opt new accounts into ReadingLists BetaFeature)
• users who did not have the hidden preference (and not enabled beta features) have the beta feature disabled
• a test user with a hidden preference (I had only one) got the beta feature as enabled; when the beta feature is disabled, the Saved pages menu option is gone, the book mark is not displayed, but Special:ReadingLists is still present - all as expected.