TYPO3 Core

For a relaunch project with TYPO3 11, the urls are migrated from a previous realurl setup with .html urls to the now standard without .html, / etc.

There are however some special pages that need to be kept with their previous url - meaning abc/def.html since external applications, mobile apps etc. load them and i can't risk or even properly test the behavior when they are served a redirect to a new url.

When i enter that slug in the page properties, the regex from the slughelper kicks in and removes all special characters
https://github.com/TYPO3/typo3/blob/597a92fd55221caaccd28628b5e03024a319ef7a/typo3/sysext/core/Classes/DataHandling/SlugHelper.php#L125

Is there a technical reason not to allow more chars like uppercase and unreserved chars?
See https://datatracker.ietf.org/doc/html/rfc3986#section-2.3
I'm fine with lowercasing and removing special chars when the slug is generated from TCA fields, but for manual editing we should try allow everything that is technically allowed.