RepeatMasker is a program that screens DNA for interspersed repeats and low complexity DNA sequences. The database of repeats to screen for can be provided as a FASTA file or downloaded from RepBase. If the RepBase option is chosen the RepBaseRepeatMaskerEdition file should be downloaded and unpacked, and the enclosed EMBL format file ('RMRBSeqs.embl') should be uploaded to Galaxy for use with this tool.
Further documentation is available on the RepeatMasker homepage.