Steps to reproduce:
* open Chrome in incognito mode
* enable "Block third-party cookies" option
* log in on en.wikipedia.org
* visit other projects
Results:
* local login works
* second-level domain login (e.g. de.wikipedia.org) works
* edge login (e.g. en.wiktionary.org, being logged in immediately after arrival) does not work
* autologin (being logged in a few seconds after arrival) does not work
* autologin when visiting Special:Userlogin does not work
While this is currently incognito-mode only, and opt-in even there, a 2020 January Chrome [[https://blog.chromium.org/2020/01/building-more-private-web-path-towards.html|blog post]] says "//Once [privacy-preserving and open-standard mechanisms like the Privacy Sandbox] have addressed the needs of users, publishers, and advertisers, and we have developed the tools to mitigate workarounds, we plan to phase out support for third-party cookies in Chrome. Our intention is to do this within two years.//" so this is probably the sign of things to come for the default browsing experience as well.
{F31933423}