The release date fields are typically associated with albums. Yate's slew of fields was initially modelled after the ID3 specification as it was and still is the most well defined specification available.

Year is typically used to represent the YYYY component of the release date and is the most common field actually used by players. This is simply by convention as that's how most players historically treated the field. Certainly this is how iTunes treats it. Yate lets you get around the limiting to YYYY restriction as many users like keeping the entire release date in it. At the low level, Year in ID3 based files is mapped to a TDRC frame which is defined as the 'Recording time'. Virtually no players treat this field as the recording time.

The 'Release Time' field is defined as the name implies. Not too many players actually read this field. Many users store a somewhat full release date here: ie. YY-MM-DD

The 'Original Release Time' field as defined in the ID3 specification is supposed to be the time when the original recording of the audio was released. However, many users store the time the track was originally released by the artist ... which is not necessarily the same.

This is all pretty confusing and is a result of the almost complete lack of standards.

The bottom line is that it's your media and you should tag it any way to want as long as it satisfies your player of choice. If your player is iTunes, it only cares about the Year field so you can pretty much do it however you wish.

Personally I tag my Various Artist releases as follows: Year contains the date the compilation was released. Original Release Time contains the date the track was released. Simply my method 🙂