Release Manager has gone through a number of iterations over the years, starting with Application Release Manager (ARM) then a bundle of Release Control (SBM solution), Release Vault (CM/ZMF), and Release Automation (Release Automation (RA), first based on Nolio, then based on what is now Deployment Automation).
We now have Release Control, which is an SBM solution based product, but in some places in various systems you will still see it called Release Manager.
At one time, RLM was part of Orchestrated ALM, and was bundled with Development Manager (DVM) and Requirements Manager (RQM), and for some versions, the installation and configuration material for these three were combined and named alm, since the installer installed all three.
The readmes and documentation give the information, but this is a history so that those unfamiliar with the evolution of the product will have some context.