Great! I always disable it.

> It's commonly used for other actions or more often getting clicked by accident, and dumping your entire clipboard while having no indication that this will happen is nothing short of a dumpster fire.

> gsettings set org.gnome.desktop.interface gtk-enable-primary-paste true

Tell me you don't understand X11 without telling me you don't understand X11.

PRIMARY is "the thing you selected" for an operation.

SECONDARY is "the other thing you selected", for an operation that takes two args.

CLIPBOARD is the interprocess data transfer mechanism.

This is why Firefox has the https://kb.mozillazine.org/Clipboard.autocopy flag. Select text in a page, and move it automatically to the interprocess space.

X11 systems have been plastering over the distinction forever.

I wish Chrome would disable it too.

Middle click is typically used for "Open in a new tab", people barely remember that it simultaneously pastes your clipboard (e. g. see https://evercoder.github.io/clipboard-inspector/) without "clipboard read" consent dialogue, which quacks like a security vulnerability.