extension code-point limit to 16 chars is too low for modern apps (showSaveFilePicker)

[tiptronic]

For our (native) custom applications we register a couple of file-extensions with the OS.
Unfortunately some of these are longer than 16 characters (including the '.').

There seems to be no way to use the showSaveFilePicker method to save any of these files:

• if we provide the suggestedName including the suffix but without types, the suffix is removed (which basically destroys the file on a user's machine)
• if we provide the suggestedName including the suffix with types, an exception is thrown if the type i (e.g. accept: {'application/zip': ['.ourRegisteredExtension']}.
• if we try a wildcard accept: {'application/zip': ['*']} an error is thrown.
• ...

The conclusion here is, that for nowadays modern applications, the extension-length limit to 16 character seems too restrictive.

Is there any chance, this restriction is lifted or made a bit more flexible - e.g. let me just enter a suggestedName including extension and have the showSaveFilePicker to not touch the suggestedName?
Or allow for longer extensions?
Or allow for wildcard extensions?

[a-sully]

FYI some discussion about this is happening over on https://crbug.com/1464953