There are still a few situations where CSS browser prefixes are needed to the feature to work on all the browsers Tuleap support (e.g. mask-image) and we are still attempting to manage that manually which is not without issues:

• developers needs to know which features are supported and find a way to make it work
• the prefixes that becomes unnecessary are left in the codebase

Handling that automatically is also more in line with our current strategy regarding browsers support.