Mapping extended attributes in customized columns in Mp3tag

I’m trying to create a new column in Mp3tag that will read/write attribute 37.

I have a list of extended attributes that Windows uses, but unfortunately some are marked as “unidentified” (or blank, unused, etc.)

I’ve been reading up on Mp3tag’s use of attributes on their site (and elsewhere), and apparently attribute 37 is a placeholder for people to put customized info in. The issue is that, since I want to map it to a custom column in Mp3tag, when I go to the Customize Columns dialog, click New, and start typing in, say, “Attr37” as Name, I then get stuck on Value and Field. What do I put in these boxes? There’s an arrow next to these fields that displays a list of available attributes, but there are literally up to around 300 choices, and since attribute 37 is marked as unidentified in all the sources I’ve checked, I have no idea what to select, or if I have to jump through an extra hoop since it’s, for lack of a better term, “nonstandard” for mp3s.

I’ve even resorted to a tiny VBA script to print out the attribute names of each attribute field, but attribute 37 (and a bunch of others) is blank.

My questions are:

First, were the sources I checked right in saying that it’s safe to use and is intended as a placeholder? (I’m using test copies of my mp3s, so I’m not touching the originals in case this is a bad idea, so we don’t have to play it completely safe.) Second, does anyone know how to map attribute 37 to a custom column? I’ve been up and down the documentation on Mp3tag, but from what I’ve found, it doesn’t weigh in on what it considers attribute 37. If attribute 37 isn’t good to use for mp3s, can anyone suggest another attribute I can put custom info in?

Thanks!