Hey!

I see that this is your first PR. That is great! Welcome!

Symfony has a contribution guide which I suggest you to read.

In short:

• Always add tests
• Keep backward compatibility (see https://symfony.com/bc).
• Bug fixes must be submitted against the lowest maintained branch where they apply (see https://symfony.com/releases)
• Features and deprecations must be submitted against the 7.3 branch.

Review the GitHub status checks of your pull request and try to solve the reported issues. If some tests are failing, try to see if they are failing because of this change.

When two Symfony core team members approve this change, it will be merged and you will become an official Symfony contributor!
If this PR is merged in a lower version branch, it will be merged up to all maintained branches within a few days.

I am going to sit back now and wait for the reviews.

Cheers!

Carsonbot

Have you submitted a PR to the upstream database to add it in there ? It is the proper way to get updates in this list (we don't want to have to maintain the full list ourselves)

Have you submitted a PR to the upstream database to add it in there ? It is the proper way to get updates in this list (we don't want to have to maintain the full list ourselves)

I have not, no. Albeit, you are absolutely right and I'll open a PR with the upstream to correct this.

Despite this, IANA assigns only mkv and mka (omitting mks and mk3d). I'll see if they're happy to also merge mks and mk3d into the main database. Since the x-matroska is deprecated (according to the RFC), there's still a good possibility we'd need to override the priority ensuring the audio/matroska and video/matroska are the preferred types for these particular extensions.

I'll get this submitted, and we can take it from there.