OK, so the question I'm looking at is clearly off-topic, but it doesn't fit one of the existing close reasons. What to do? Of course! Use a custom close reason.
Hmm, what to put there?
This question appears to be off-topic because it is about program management.
Hmm, isn't that programming related? Am I talking about pointy-haired bosses, or about version control?
This question appears to be off-topic because it is spam/nonsense.
Fair enough, but wouldn't a moderator flag have sufficed?
This question appears to be off-topic because it is not about programming.
Is that suitably descriptive?
This question appears to be off-topic because it is about [the question title].
Hm, really?
The custom close reasons are the least defensible of the close reasons, because they appear ad-hoc (we're making them up as we go along). But writing custom close reasons is hard. Writing a good reason seems to be as difficult as writing a good question title.
My idea of a perfect custom close reason is this:
This question appears to be off-topic because it is about [general topic area defined by the question] and not about [one of the general topic areas in help/on-topic]. See [Meta post where we discussed questions like this, and established a community consensus that they are off-topic].
... but we really haven't provided a lot of guidance on how to use custom close reasons, other than filling in the blank. Could we do better at this, and if so, how?