[R] unknown compression

[R Heberto Ghezzo, Dr]

Hello, I am trying to modify some functions in an existing package. I can get a function by just typing the name in the console, but how can I get all the functions in a package? the ./R/ subdirectory has files xx.rdb and xx.rdx which I can not decompress with 7-zip or with unzip, unrar etc. The help files are compressed with gzip in the ./man/ folder and can be unzipped easily.
Thanks for your help
heberto.ghezzo at McGill.ca