This one with Ted Nelson? https://youtu.be/RVU62CQTXFI

It's got the skeptical interviewer, and at 9:56 (with some lead-in before) there is a discussion of libraries, catalogs, tagging, etc.

Edit: and then he goes on to mention Dewey Decimal as well.

Yess!! THANK YOU! For all these years, I couldn't find it. I appreciate this so much, thank you :)

Welcome :)

It appears to be a "MacWrite II document" according to http://mark0.net/onlinetrid.aspx

Thanks for the link! I had tried running `file` on it, with no success ;)

It is definitely not MacWrite since it doesn't conform to the format:

http://fileformats.archiveteam.org/wiki/MacWrite

Looks like it is actually Word for Mac:

https://www.w3.org/History/1989/proposal.html