understanding boards.txt / programmers.txt

In the past I used to change boards.txt to reference entries in programmers.txt in order to use an isp instead of the bootloader. With Arduino Uno it seems that the entries in programmers.txt are not referenced by boards.txt anymore. Instead it seems to directly reference to avrdude.conf.

Has anyone a hint for me why programmers.txt still exists?

The entries in programmers.txt seem to show up in "Tools->Programmer". After you select one you can use it by selecting "File->Upload Using Programmer". No editing of boards.txt needed.