[orforforof]

For many of the papers I read (engineering) I would love to be able to click on symbols in an equation and have it link me back to where that term was first defined in the paper, either in another eqn or in the text. Tracing back in this way is a major pain point e.g. when trying to reproduce calculations. Seems like something journals/latex could easily implement in an automated fashion (maybe already possible?)

[diarrhea]

I use glossaries-extra. It allows the usual glossary stuff (acronyms), but can also be used to define symbols. All symbols then become hyperlinks, linking to the nomenclature at the beginning or end of the document. And in that nomenclature, glossaries- extra allows one to have a column of "first used", specifying the page of first occurrence.