Going to https://translatewiki.net/w/i.php?title=MediaWiki:Smw-limitreport-intext-parsertime-value/en&action=edit one can see "Message definition (Ores)".
Hence removing MediaWiki-General from this task and setting ORES instead.

Basically, when you set threshold to hard you give it a high number so less edits will be flagged for review but chance of being vandalism is higher. On the other hand when you set it to soft, it flags more edits so you might catch all vandalisms but proportion of vandalisms would be less and you see more false positives (edits that are flagged for review but they are completely okay edits)

I was well aware what thresholds are and how they work.
I have copied the the above explanation to the message documentation /qqq in case some translator does not know about thresholds, slightly modifying it for better readability.

I still have no clue what I should do with Name of "Soft" threshold which I do not understand at all and which is not a helpful explanation of the message and its use to me.

I was able to translate the message now, regardless, as several colleagues had translated them to languages that I understand. My translation translated back to English is: Soft (less strict)

Actually Soft is lower threshold which means it will flag more edits (=more strict) but since I can relate to bots more than I can do with humans, I trust you and I'll change it to "Soft (less strict)" (and change everything inside the code so it'll flag less)

Change 267837 had a related patch set uploaded (by Ladsgroup):
Change concept of hard and soft in order to make it intuitive

https://gerrit.wikimedia.org/r/267837

Change 267837 merged by jenkins-bot:
Change concept of hard and soft in order to make it intuitive

https://gerrit.wikimedia.org/r/267837