Simplify the following text for a Grade 15 native English-speaking person.
Original: Unreleased material ( including demos , mixtapes , bootlegs , promo-only recordings ) are in general not notable ; however , they may be notable if they have significant independent coverage in reliable sources .
Simplified: Unreleased material such as demos , mixtapes , bootlegs , and promo-only recordings do not in general have the significant independent coverage in reliable sources needed for independent notability .