When I double click on local .deb file it doesn't install directly, instead it opens in read-only mode in Ubuntu 22.04LTS (Screenshot attached). To install the same I have to right click on .deb file > open with other application. Then a recommended applications prompt opens. From there I select software install to install a software.
A .deb file is a compressed archive, and the file-manager program is treating it as such. eg. if I explore a .deb file it's contents are reported as
Debian binary package (format 2.0), with control.tar.xz, data compression xz
but it can't know what OS/release its for, as it may not be your own, so it's safer to treat it as what it is - a compressed archive.
ps: the .deb file I used as example is not for my OS/release system & I'd for one not want it installed automatically on click; not even attempted to install!
If you're looking to install the dpkg file, you should try running this:
sudo dpkg -i ./myapp.deb
The above command installs the Debian package.
A quick heads up: You should only install packages if you trust them.
Debian binary package (format 2.0), with control.tar.xz, data compression xzbut it can't know what OS/release its for, as it may not be your own, so it's safer to treat it as what it is - a compressed archive. (ps: the .deb file I used as example is not for my OS/release system & I'd for one not want it installed automatically on click; not even attempted to install!) – guiverc Aug 30 '22 at 11:49