I've recently commented a question being off-topic asking for software / product / service recommendation.
The OP commented he thinks it's on-topic as it's not "software / product / service"
I believe those are off-topic:
- even if they aren't subjective, they require link only answers and links can broke / change at any time
- majority of documentations aren't hidden on the web, if you can't find them by a google search then there is a high chance they don't exist, in this case we can't help, best to contact the developer / owner.
Are documentation requests on-topic on superuser.com?