Where can I find-Issues(plugin) and Issues(Core)

Issues (Core) means that the emulator itself doesn't support the Rom. Sometimes changing to interpreter will help - if this is the case, then a note will be besides the rom to mention that.

Issues (Plugin) means that the default plugin with PJ64 (Jabos D3D) doesn't support the game fully. It may still work - but not
properly.

The first issue cannot be fixed, beyond selecting interpreter, and/or trying a different emulator that may support it.

The second issue can in many cases be fixed by using alternate plugins - try reading some of the posts on this forum to get an idea about what you should try.

No, if a game needs the interpreter (for example) it can still be Compatible, it will be commented as "slow" etc. Any kind of Issues cannot be fixed by the user, since if they could be, they would be, or you'd be told what to do.

If that was a reply for me Smiff, then I think I said pretty much the same thing in my post. Otherwise just ignore me

What you said was not wrong but it suggested that he could do something about it, which he can't. So like you said, change plugins or core. I don't specifically state (or know, often) what plugins or core you should use because that's none of my business.