What
A plugin id has the form plugin@marketplace: the plugin's name, then "@", then the name of the marketplace (the catalogue) it comes from. The error shown for an invalid id has been reworded.
- More than one "@": the message now says so, explains that either the plugin's name or the marketplace's name contains one, and that whoever named it can rename it.
- Hidden characters: the message adds a note when the name contains a character that is not shown in the message.
Before, the message only said that each half must begin with a letter or digit and hold only letters, digits, "-", "." and "_".
Why
When a plugin fails to install because of its id, the message now points more directly at what is wrong with it.