REQUIRES_COPYLEFT -
derivative and combined works must be licensed under specified terms, similar to those of the original work
REQUIRES_LESSER_COPYLEFT -
derivative works must be licensed under specified terms, with at least the same conditions as the original
work; combinations with the work may be licensed under different terms
REQUIRES_NOTICE - copyright
and license notices must be kept intact
REQUIRES_SHARE_ALIKE -
derivative works must be licensed under the same terms or compatible terms as the original work
REQUIRES_SOURCE_CODE -
source code (the preferred form for making modifications) must be provided when exercising some rights granted by the license