[GFSD Issue] file-roller sugests non-free packages for rar archives

When trying to open a RAR file with file-roller, a dialog appears:

Could not open this file type

There is no command installed for RAR archive files.
Do you want to search for a command to open this file?

After clicking on "Search Command" button, the program suggests non-free rar packages:

Could not find requested packages

file-roller requests to install the following software packages to provide additional features:
• rar
• unrar