Wordpress team always uses いじります
for fixing/editing code files. I somehow can understand it is "Editing", or "Fixing", or "Modifying".
But I just want to know it clear. Google translated to "messing around", or "playing toy" :D
Below is the sample WordPress team used to modify some files, they wrote this message to inform other members do not touch those files. (They are not good at git and they don't have good environment to develop and control source code!)
wordpress\themes\abc\header.php
wordpress\themes\abc\css\layout.css
いじります。