Question about BuSL / transform-on-time licenses

Hi all,

The Fedora Project is discussing how to properly represent code that
was originally licensed under the Business Source License (BuSL) and
other licenses that transform on time. [1]

Specifically - let's say there's a project that uses the Business
Source License (BuSL) and is supposed to convert to GPL after N years.
Obviously, the GPL is an acceptable license for Debian - but what steps
would be required to ensure the entire codebase had converted so that
no parts would still be under BuSL?

I'm wondering if the Debian Project has a position on this that's
documented somewhere, or if this has come up yet? I'm specifically
interested in how the project would address risk / confirm that the
whole codebase had transformed or if Debian would avoid a (formerly)
BuSL licensed project entirely. [2]

I'd skimmed through the archives but haven't found anything - which
doesn't mean it does not exist, I may just have failed in my searching. 

[1] https://lwn.net/ml/fedora-legal/CALC7GWw7F5Bz_+5GTGW1+3xz1DZg5RLn=Bxi-r7Rt_x0UqNAow@mail.gmail.com/

[2] https://lwn.net/ml/fedora-legal/CAC1cPGztsUD5D5xo4aUKpgypwVZ+rzE_PZVnMNEb-_pkGg+Mqg@mail.gmail.com/