By the other hand in the case of Slack, as it happens with a lot of "software as a service", it has multiple apps for different platforms, web, Windows, Mac, Android, iOS. In someway the question body should make it clear that the question is about using or direclty interacting with the web app as on this site only questions about using web app are on-topic.
Is specifying whether one is using the web version of the product of interest in the question a requirement on https://webapps.stackexchange.com? (requirement = the question will be closed if not specified)
I'm surprised as:
- Many tags clearly indicates that the OP is interested in the web version, e.g. the slack tag clearly indicates:
Use for questions about the Slacks's web version accessible from a browser. Questions about the installable versions are off-topic on this site.
- If that was the requirement, many questions should be closed.