Opening Manage Language Packs module modifies LocalConfiguration.php
The LocalConfiguration.php get's updated when you load the "Manage Language Packs" module in the new install tool of TYPO3 >= v9.5.
- I have AdditionalConfiguration.php which persists some of the TYPO3_CONF_VARS.
- If the "Manage Language Packs" module is opened and loaded from the server (you have to re-open/-load the Maintenance module before)
In my case
EXTENSIONS/backend/loginHighlightColor was updated with the value of AdditionalConfiguration.php
It's not really a big issue, but it would be perfect, if the files are only modified if you intend to change that (and get notified about the change).