Individuals, institutions and firms who contributed code to QGIS can let people know about their contribution by:
adding a short note on the commit itself (something like “Funded by …); please keep wording to an absolute minimum
adding a note to the changelog for the first version where the code has been incorporated, of the type:
This feature was funded by: `Olmiomland <http://olmiomland.ol>`
This feature was developed by: `Chuck Norris <http://chucknorris.kr>`
If you have questions, feel free to contact us: psc@qgis.org