Apple Macintosh: Is the "File System Manager" Extension available anywhere?

I'm using the Basilisk II (68k Macintosh) emulator with MacOS 7.0 and 8.0.

File system sharing (between host and guest) works fine with 8.0 but I also want to use it with 7.0.

According to the manual, to use file system sharing with MacOS 7.0 or 7.1, you have to install the "File System Manager" extension in the guest operating system. (Newer MacOS versions do not require the extension.)

Is there any source where I can get this extension?

Here is where I already searched:

I found some links to retrocomputing repositories where the extension can supposedly be downloaded. However, all links I tried only contained the "File System Manager SDK" which only contains the SDK for the extension but not the extension itself.

Supposedly the MacOS 7.5.0 and 7.5.1 CD-ROM ISOs (but not 7.5.2 or newer) contain the extension. However, the ISOs I found did not contain the extension. (However, I have the suspicion that I did not get the correct ISOs.)

The information that certain other extensions (like "Joliet File System") contained a copy of the extension turned also out to be wrong.