Allow to use a custom file size limit per file type

Seems to work. I would suggest adding file size hints.
This patch requires to seperate 'Default allowed file extensions' in spaces only. It will throw an error if you are using a comma

This works well for me. #5 is true, but it turns out that's actually a bug in Drupal core. Despite description text indicating that either comma-separated or space-separated values are ok, file_validate_extensions() will very clearly *only* work with space-separated values.

Actually, I looked a little closer and comma-separated values *are*, in fact, allowed by core. It cleans up these commas in _file_generic_settings_extensions() before saving the list. File Entity, however, doesn't add that particular validation function to this field. I've taken out that issue: #2796065: Default allowed file extensions help text is inaccurate; comma-separation is not allowed

But that shouldn't hold up this patch.

Meant to mark RTBC.

Is this added in yet? Looks like not, correct?

It's late for the last release. Although I could stick it into the 7.x-2.x dev and 7.x-3.x dev branches.
patch still applies correctly, although it leaves some garbage .orig files.

I believe #2796065: Default allowed file extensions help text is inaccurate; comma-separation is not allowed
should also be committed with this.
make sure both patches pass tests.

I realise it's been 4 years, the patch still applies though.

Anyone still want this functionality in the next release?

Editted

We still do, thanks for the update.

ok, I tested this, seems to work well.

This is in dev, most likely will be in the next release.