Xpra: Ticket #2775: Xpra 3.0.10 not working in HTML client

Hi,

I use Xpra on Debian 10 to view an application in the HTML5 client. I build the Debian package for the LTS version 3.0.10 from source. The most recent revision doesn't work for me, the HTML client keeps restarting. (xpra v3.0.10-r26457)

I can recreate the bug with the command:

xpra start --bind-tcp=0.0.0.0:8888 --start=gedit

And logging in through Firefox on the localhost.

The problem seems to be introduced with this commit that uses guess_content_type: r26327

reverting the change fixes the problem for me.

I haven't tested the official builds and don't know if it is just my build.