What is the SID Tune Information List (STIL)?

See ​https://www.hvsc.c64.org/download/C64Music/DOCUMENTS/STIL.faq. The most relevant fields provided by STIL are:

• the NAME field
• the AUTHOR field
• the TITLE field
• the album subfield
• the ARTIST field
• the COMMENT field
• the TIMESTAMP subfield

Should we keep extra information in STIL or put it directly into tags in SAP files?

As I resisted STIL for many years, here's how I got convinced to it: (pfusik)

1. It's very well documented.
2. We have lots of existing entries.
3. It was easy to support it in ASAP.
4. SID players require the user to locate the STIL file. But if you search for the file automatically, no user intervention is required to show her additional potentially interesting information.
5. The information is easy to understand if you reformat it instead of showing it as-is.
6. Ramos was lobbying it all the time. ;)