PLUGIN — installing and running plugins

Raised while a plugin is installed — from a directory, a git source or the catalogue — updated or removed, and by the checks an installed plugin contributes to the doctor. An install that fails part-way is put back: the plugin’s files and container go, and the change record says what was written and reversed.

The release this page is built for does not carry what this part is read from. The next version's page has it.

What each severity and each exit means is on every error by code, beside every other family.