There is only one other one-off ebf for RS 15.5 that is available for download in the archive section and that is ebf 19223 and it contains one fix in the ebf for repserver that fixes Open Server issue:
CR 672294 Update the open server components of replication server to provide essential open server vulnerablility fixes.
If this is what you are looking for it is available in the software downloads in the archived section at the following link:
https://support.sap.com/software/patches/archive/a-z-index.html
I would encourgage upgrading to a newer version of RS as soon as possible this is very old version of RS.
Terry