Youtube Embed automatically removes additional classes

[SleepyEvoli]

Description

When you add an additional class, save and leave the editor everything works fine. But as soon as you open the page editor again with that Youtube embed, the additional class gets removed.

I use the standard Youtube embed.

Step-by-step reproduction instructions

1. Start editing a page or a post
2. Add Youtube embed
3. Add additional class to that embed
4. Save
5. Open the editor again

Screenshots, screen recording, code snippet

No response

Environment info

Wordpress 6.1.1

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[skorasaurus]

Hi,

Thanks for reporting;
This has already been reported in #46627. Feel free to add your reaction and follow its progress in the issue.