While changing variable names in a project indented with tabs, KDevelop tends to prepend a bunch of extra spaces if it's not done manually. 

STEPS TO REPRODUCE
This is visible via automatic renaming (context menu -> Rename X), but a tiny bit more simply by renaming a variable, switching to one of it's users and then accepting the suggested solution from the popup ("Replace X with Y").

OBSERVED RESULT
3 (!?) spaces are erroneusly prepended to the name (so after the leading tab).

Here's a three-step journey laid bare:
https://imgur.com/a/bMLmxHi

Observed with earlier versions, but it's still there in 5.6.0, so finally got the idea to file a report.