The upright parameter has the following format:
upright upright=$1 upright $1
Localized for de.wp are shown as:
hochkant hochkant=$1 hochkant_$1
But the last option (hochkant $1) is shown as linter error when written with space instead of underscore.
https://de.wikipedia.org/w/index.php?title=Fernfahrer&oldid=164516741&action=edit&lintid=13782
It is possible that there also other alias have different in underscore or space, because translations from translatewiki.net are always written with underscore