On 5 Sep 2019, at 23:28, Carpii UK wrote:

It would be very useful if TM would register itself with OSX in the same
way.

I would love to have TextMate in that menu, but I have no clue what Apple expects.

TextMate declares support for document types with the following criteria:

CFBundleTypeExtensions = ( '*' );
CFBundleTypeOSTypes    = ( '****' );
LSItemContentTypes     = ( 'public.data' );

Quite sure that in the past, I got TextMate added when I added public.data but that no longer works.

I see e.g. Script Editor in the Open With menu, looking at their Info.plist I don’t see anything declared there that TextMate doesn’t also declare.

So if anybody knows how to get TextMate added by default, please let me know.