IMPORTANT:
Ungoogled Chromium does NOT work with a classical installation of Flatpak like
sudo apt install flatpak
You must add the repository (at least for Ubuntu). See the link:
https://flatpak.org/setup/Ubuntu/
I suggest to add this information on the flathub page for people because this information does not appear here:
https://flathub.org/apps/details/com.github.Eloston.UngoogledChromium
For people who want to add extensions in Ungoogled Chromium, this is turned off by default so to change this behaviour:
1- Go to
chrome://flags/#extension-mime-request-handling
and change it to:
Always prompt for
2- Chrome Web Store
3- choose your extension, for example ublockorigin and copy the url, so:
uBlock Origin - Chrome Web Store
4- go to this website to extract the extension of ublockorigin:
https://crxextractor.com/
click on “Start for free”
copy and paste the url of ublockorigin
click on “Download”
click on “Get .CRX” (.crx file, the ublockorigin file)
Click on “Add extension”
Done !