In Artwork for FLAC files 'block r/w' refers to the well defined method of storing an image. The image is stored in binary outside the Vorbis Comment containing the text based tags. It's stored as a FLAC 'block'. Yate reads and writes these images. Very old FLAC files may contain base64 images stored as text based tags named METADATA_BLOCK_PICTURE or COVERART. FLAC text tags are called Comments. Yate will read these images correctly but will not write them. These images are grossly inefficient as they are far larger than the raw binary image and eat away at the size limited tag area.

The FLAC mappings are almost completely user configurable. The tag mapping table describes the out-of-the box mappings. For any given FLAC tag, Yate can read numerous variants of the tag but will write only one. So out-of-the box Yate will set the Original Release Time field from tags named: ORIGINALDATE, ORIGINAL YEAR, ORIGINALRELEASEDATE and ORIGINAL_YEAR .... but when it writes the files the field will be written as ORIGINALDATE.

By having R/O and R/W mappings you have a high probability of reading and mapping the fields correctly.

The out-of-the-box defaults were chosen to offer a high degree of compatibility with various other taggers and players.

... and questions are never a problem.