In latest JMeter there are irrelevant plugins in Plugins Manager (start with jmeter - ) as jmeter - JDBC Support
It display JMeter components which are part of JMeter and can't be uninstalled,
Manager UI allow to uninstalled and if clicking Apply Changes and Restart JMeter
it seems to have no real effect, but it's still very confusing.
It seems like a bug, but is it Plugin manager issue or JMeter? is there some purpose for displaying JMeter core features as plugins? can it be removed?
As feature is provided by plugins-manager, it is a plugins-manager issue.
I would suggest you report it on their forum.
The idea was to remove plugins (even core jmeter) that were not used.
As you know, Apache JMeter is built with Plugin Architecture in core, all protocols are plugins even core ones.