Answer select
"Confirm reassign this pattern to file type 'APK'"
Why?
File pattern in android studio which is another version of intellij idea IDE, has a very good suggestion engine.
To suggest us the typos and mistakes in syntax, it must know which programming language is used in the file, so that it can suggest us / show us errors accordingly.
For example if you create a file "hello.xyzabc" which has simple html code in it, you will have to tell intellij idea IDE (android studio), that this file is actually an html code file, so that regardless of extention being completely different, it shows us suggestions / errors, just like a html file.
We do this in android studio (bumblebee version 2021.1.1) through
Settings|Editor|File types
[have denoted android version, because sometimes they change menu item position]).
They (intellij people) keep on adding recognition defaults to improve suggestions.
In this case ".apk" is not actually a zip (archive) file, even if you can open it with "zip" application.
so to get suggestions regarding ".apk" files in future you must select
"Confirm reassign this pattern to file type 'APK'"