Unknown file formats have adwaita icon

[SolsticeSpectrum]

I am running Chicago95 on latest Xubuntu
In this example the .xpi file is adwaita icon instead of Chicago95 icon

[1chan-level-journalist]

I've had a similar issue. I fixed it by doing the following:

1. Go to /home/user/.icons/Chicago95/mimes/48/ (I'm assuming your icon size is 48 pixels)
2. Here you'll need to create an icon called "application-x-generic.png" - I just copied the "text-x-preview.png" icon and renamed the copy.
3. Open terminal and enter the following: sudo gtk-update-icon-cache /home/user/.icons/Chicago95/
   That should do it.
   Or, if you installed the theme as a root user, the path should be /usr/share/icons/Chicago95/mimes/48/.

[SolsticeSpectrum]

@1chan-level-journalist Thank you so much! Yes that fixed my issue, also as a side note I did the same thing for all sizes, not just 48, aka 16, 22 etc ...