I've just exported an EPUB from InDesign CC 2014, and I've noticed some odd id tags scattered throughout the text at apparently random locations (in between words, etc) -- there is also one right at the beginning of the HTML content. They look like <a id="x.16448"/> (that is the first one) and the five-digit number always has 16 in the beginning, but increases in increments of about 3-9 as I move through the book.
The print edition of this title had an index, but I've deleted all the index reference tags already. I don't think it's related to the TOC either. Any ideas? I can regex them out easily but I'm just curious.
Sounds like some sort of Text Anchor.
You would need to go back to the source file and see what magic character is inserted at that location.
Turn on "Type/Show Hidden Characters" and then tell us what the blue character is.
Architect, InDesign Engineering
I went back and turned on Hidden Characters and there are two dots there (like a colon). I've seen this mentioned elsewhere on these forums in a discussion about TOC hyperlink errors on EPUB export:
So I guess they are unused hyperlink destinations, and they can be deleted in ID. But I'm not sure I understand how they ended up in my text.