I just started with the JASPIC to Jakarta Authentication spec document conversion, and just a heads-up for anyone who hasn't started yet: it's quite labour intensive.
Tables are completely missing, image captions are mistaken for headings meaning section numbering and hierarchies are all wrong, even chapter numbering can become all wrong, footnotes are missing, etc etc.
This is far more than just a semi-automated search & replace for terms as with the Javadocs adjustments for Jakarta EE 8.
Basically it boils down to reading the entire document, adjusting errors wherever you see them, compiling the PDF, checking it's correct now and repeat that.
Absolutely doable of course, but just taking a fair amount of time.