Translations:Handbook:Parts/Installation/Base/144/en
From Gentoo Wiki
For the convenience of system administration, legally-similar software licenses have been bundled together - each according to its like-kind. License group definitions are available for viewing and are managed by the Gentoo Licenses project. While an individual license is not, license groups are syntactically preceded with an @ symbol, enabling them to be easily distinguished in the ACCEPT_LICENSE variable.