This is actually not an ask but a guide for those using Yate to curate the metadata of their libraries, and specifically for how to add WORK and PART (which are not standard ID3).
I found it a little confusing how to do this, so here is the solution:
In Yate:
1- Preferences > Audio > Common - At the bottom there’s an “Application presets” - Choose Roon. This will define the custom fields Roon likes.
(You can check custom fields defined in Preferences > General > Custom Fields)
2- Right-click on the editing panel on the right, go to “Edit Custom Panels” and create a custom panel which you can call "Roon”. Then add the Roon tags you want visible by right-clicking on “Unused” buttons on the left of the edit screen and choosing the field you want. Save it and now you can bring that custom panel into the edit panel.
This turns out to be a better solution than using Metadatics because the new variables are always available - you don’t have to add them every time you need them.