The use of the figcaption element as a child of figure to provide non-text content for an image that is also a child, seems like, at the least, an acceptable method of providing a long text alternative technique for Sitaution B of 1.1.1.
However, there do not seem to be any techniques employing figcaption.
I would like to understand if this is just a gap in the tecniques guidance, or if there is a reason figcaption is being disfavoured as a means of offering non-text content text alternative.