What's wrong with this entry?
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Plugin installation now checks if a plugin is already installed before attempting reinstallation. If a plugin with the same name and scope already exists, a clear message is shown: Plugin '<name>' is already installed (scope: <scope>).
Evidence
Plugin duplicate check (search for "is already installed") — CLK at line ~229155
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
Related
Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.