expression, noun which may take the genitive case particle 'no'
not included; unrecorded
Used for something that is not included in a compilation, album, list, or official record. Often appears in contexts like bonus tracks, unreleased material, or omitted entries.
この曲はアルバムには未収録です。
This song is not included on the album.
未収録の映像が特典として付いてくる。
Unreleased footage comes as a bonus.
未発表 means 'unpublished' or 'unreleased', focusing on something not yet made public, while 未収録 simply means 'not included in a specific collection'.
Compound of 未 (mi, 'not yet') + 収録 (shūroku, 'inclusion, recording').