Pretty straightforward question. What labor is used for the prayer dwarves? I believe it is strand extraction, but my dwarves that have it enabled won't pray. I just want to know so I can be sure that it is something I'm doing that is unrelated to the mod.
Prayer is, indeed, the job formerly known as strand extraction.
Prayer is also performed at one of the religious buildings; dwaves don't just pray anywhere. This is going to sound silly, but have you built any of them? In version ☼6.2☼, the simplest of them, the Shrine of Armok [b]-[w]-[alt-H] only requires 2 blocks. In previous versions, it also required candelabras.
If a religious building does exist, the question becomes 'why aren't my dwarves using a workshop?', and the usual checklist applies: are other jobs interfering, is access available, are there any missing reagents, do burrows get in the way, etc.