Registering Download Plug-ins on non-Windows Relays

We have a requirement to configure some of our Relays to pull content directly from the Internet (rather than go up the hierarchy to the BigFix Server). This is due to network utilisation constraints.

We are using Linux-based Relays for this purpose and have configured these with settings:
_BESGather_Download_CheckParentFlag=0
_BESGather_Download_CheckInternetFlag=1

Next, my understanding is that I need to Register Download Plug-ins on the Relay itself (in addition to the BigFix Server). Here lies my problem. When I go into the “Manage Download Plug-ins” none of my Linux-based Relays are listed, only my BigFix Server (hosted on RedHat) is listed.

I have completed the prerequisite steps:

Activate “Download Plug-in Versions” Analysis
Activate “Encryption Analysis for Clients” Analysis

I did look to take action on the “Enable Encryption for Clients” Task, but noted that this was not relevant for these Relays - the relevance clause only selects Windows computers.

Based on the above, and from what I have read in the BigFix documentation, it suggests to me that the registration of Download Plug-ins on Relays is only supported on Windows-based Relays.

Please could anyone confirm or otherwise clarify my understanding?

If this is only supported on Windows-based Relays does anyone know if there is a workaround or some alternative solution where Linux-based Relays are being used to pull content directly from the Internet? We are also constrained into using Linux-based Relays, so we cannot unfortunately simply switch to Windows.