"Coding style change" refer to the situation when inline comments, spaces, indentation, variable/funciton names are changed to comply with Moodle coding styles.
This issue is not about phpdocs changes.

Can we accept such changes in the following cases:

1. Several lines are changed to compy with Coding Style in the same commit as bug fix/improvement and are in the same piece of code as the actual fix.

2. Many coding style lines are changed in the same file as actual bug fix/improvement.

• in the same commit as bug fix
• in the separate commit

3. Coding style is improved in the file that was not affected in the actual bug fix/improvement

4. There is a separate issue that changes the coding styles only

• in one often used library file or accompanies the issue with bug fix in the same file
• massive change in many files
• the issue also contains unittests or behat tests that ensure that each changed file/function is tested
• the issue changes the files that were not modified for a long time

5. "Change that does not break anything if accidentally backported in some cherry-pick of bugfix".

• for example: change function call $OUTPUT->BOX() to $OUTPUT->box()

Cons of coding style changes:

• possibility of creating a new bug
• possibility of creating problem later when working on bug and changing the same lines (for example, new variable name is cherry-picked into the stable version)
• git blame does not show actual code changes