Is there a list of all available Appain Example Images somewhere(example: a!EXAMPLE_RECEPTIONIST_IMAGE())? I find them easy to use to quickly put together a POC.
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Good question - the example you've provided seems to straddle the line between normal and "unpublished function" (which are, technically, unsupported). The main difference is that in this case, instruction text is shown once the function name is completed, which is (usually?) not the case with unpublished/unspported functions. I guess this one (and ones like it) might be in an in-between category i.e. "for training use only" or something.
To answer your question: i'm unaware of any such list, and I doubt whether there's any "official" list published, though you might discover more via the "blind dart throwing" approach and/or searching through recipes / patterns / community-editiion-site training interfaces.
I'd be curious to hear anyone else's findings and/or official explanations here.