Try searching for these keywords using Ctrl + Shift + F:
“loadstring” - Runs code inside of a string
“require” - Gets a module from the web
“MarketplaceService” - self explanatory
“string.byte” - turns strings into byte form
“string.reverse” - reverses strings (useful for obfuscation)
“RunService” - can be used to check if the game is running in studio and disable shirt spam if in studio.
Send over any suspicious scripts so i can analyse them
Here are the links:
https://www.roblox.com/library/1871760507/Animation-Editor-Classic
I even removed other plugins to see if that pop-up gone, but it still appears.
Can you open it and send the code?
Just double click on the search result.
That certainly is.
It’s using bytecode of ‘require’ to retrieve the function through getfenv.
Any honest script shouldn’t be trying to hide require calls.
This is a good example of why just searching for keywords might not work. When scripts can be obfuscated your only option might be to inspect every script in the game by hand. You can do this by pressing Ctrl-P and checking “script only” in the dropdown box. That will display every script in the game.
Before doing that, you should also go into studio settings with Alt-S and checking these “Explorer” options under Studio:
That is definetly doing require()
Disable the script or remove it completely, publish and test.
Also, this plugin: https://www.roblox.com/library/1871760507/Animation-Editor-Classic
Is not official, was this intended?
I’m going to analyse this plugin’s source to see if it does anything malicious.
Judging by the search results for “RunService”, however, i think the cause is a fake “Brick cutter” plugin.
I’am actually searching the plugin’s source.
Edit: Nvm.
It worked. That pop-up no longer appears to me. I will do the same in my other places. Thank you so much.
Later I’ll tell you how it went.
Again, thanks for the help. I did the same steps and the annoying pop-ups don’t appear anymore. I was so stressed with it. 
And regarding plugins, can I install them normally? because I’m worried that it will reappear again.
I recommend reinstalling your plugins one at a time and searching those keywords again. If anything pops up after that plugin install, the plugin is fake and is the plugin inserting the script.
If you do find any bad plugins, please send me the link so I can analyse them
