in the “Items” section at the bottom of the source record, it might be nice to have additional check-boxes or a menu for the following scenarios:
“fragment”
“text only”
“index only”
“catchword only”
[possibly also “contrefactum”?]

This way, the sources listed in composition records could have and additional parenthetical (frag.) or (index) or (text source) appended to them.
A great case study for this would be Flos/Celsa (https://www.diamm.ac.uk/compositions/382/) or Zolomina/Nazarea (https://www.diamm.ac.uk/compositions/236/),both of whose sources are a mix of complete, fragmentary, indexed but lost, and text-only. (The latter also has a catchword at the bottom of the page in NAL 2444, though it is not included as an item in that source.)