These are the sources for TRIPOS, an operating developed between 1976 and 1982, headed by Dr Martin Richards and others between the University of Cambridge and later University Bath (origin of the MC68000 port, used as the foundation of AmigaDOS). You can find more out about the history of this operating system on its Wikipedia entry.
The license is unclear, but permission was given from Tim King to share the source publicly. I offer my thanks for this generosity.
I am not familiar with build procedures; almost certainly, a BCPL compiler is required. This was available in various forms, and appeared in various development kits for the Amiga such as the driver development kit, amongst others. Since these packages are certainly still under copyright, I cannot assist in finding them, but other BCPL compilers surely exist. Without those build instructions this may simply serve as a historical curiosity.
The source code contains ports for the Data General Nova, DEC PDP-11, Computer Automation LSI4 and Motorola 68000-based systems.
I am not the author. But I can be contacted via my GitHub account.
I received the following email from Tim King regarding the sources during a communication back in 2017. Should anyone dispute this please contact me immediately and I will be happy to deactivate this repository.
Date: Thu, 15 Jun 2017 16:42:56 +0100
From: Tim King <redacted>
To: Rob Andrews <redacted>
Subject: Re: Unusual request: Some old MetaComCo software for the Sinclair QL
Yes the s/w is public. If you have a BCPL compiler for AmigaOS you might
well also have asm.
> Rob Andrews <redacted>
> 15 June 2017 14:55
> Hello again,
>
> Thanks for your response - do you mind if I share the source with the
> people I'm working with on this? I assume the archive shouldn't be
> shared onwards?
>
> Thank you again for your help - we have a BCPL compiler for AmigaOS so
> we'll try to see about building the assembler for that host system.
>
> Kind regards,
> Rob Andrews.
[rest of email trimmed for brevity]