I have installed todays V5 nightly and tried to start how it works from looking some demos.
But when in KiCad main window I tried to open any project by (File/Open Project…) I could’t find any *.pro files.
At the and I supposed they were not installed, but checking directly on disk I see them.
I found that if I change language from Default (means Polish) to English KiCad sees *.pro files.
I wonted to report a bug but it is there (#1740481). Looking through it I am suprised that they decided to not repaire it as it is up to translators.
I suppose (not sure) that project files has the extension .pro in all languages so in my opinion the problem of using *.pro filter in that window is not translators problem.