Yes, Adobe Flash is obsolete since the end of 2020. No point being in the documentation 🙂

Firefox ended support for Adobe Flash in Firefox at the end of 2020, as announced back in 2017. Adobe and other browsers also ended support for Flash at the end of 2020.

Firefox version 84 was the final version to support Flash. Firefox version 85 (released on January 26, 2021) shipped without Flash support, improving our performance and security. There is no setting to re-enable Flash support.

https://support.mozilla.org/en-US/kb/end-support-adobe-flash

https://github.com/freebsd/freebsd-doc/pull/279/commits/6a76c8f49f7b3cad01d52dafa5c4b605295b5ed0