GitHub uses a library called Licensee to identify a project's license type. It shows this information in the status bar and via the API if it can unambiguously identify the license.

Currently, Licensee does not properly detect Foreman's license as GPL 3.0. When I run Licensee locally on the remote Foreman repo, here is the output I get:

$ licensee detect https://github.com/theforeman/foreman
License:        Other
Matched files:  LICENSE, README.md, package.json
LICENSE:
  Content hash:  a17b7fcbdc64255d04d0b05e6642373a8ccdf97f
  License:       Other
  Closest licenses:
    GPL-3.0 similarity:   77.68%
    AGPL-3.0 similarity:  74.68%
    LGPL-2.1 similarity:  53.60%
README.md:
  Content hash:  18f341307338ee217d08193931fa550b30ed563b
  License:       Other
  Closest licenses:
    WTFPL similarity:    5.00%
    MS-RL similarity:    2.34%
    BSL-1.0 similarity:  1.75%
package.json:
  Confidence:  90.00%
  Matcher:     Licensee::Matchers::NpmBower
  License:     GNU General Public License v3.0