Hello,
I am new to Linux, but I am enjoying my Librem 13 very much. I am having a similar problem, only it’s my “Software and Updates” app that has disappeared. My computer is not listing it as installed anymore and I can’t find in in the Software “store” anymore either. I didn’t purposely uninstall anything. The problem happened after I connected my computer to WIFI in a hotel, though I don’t know that there is a connection between the two events. Will the solution for restoring the Software “store” app work for restoring the “Software and Updates” app too? Thanks!