Question from the old school: source config DSL

[Robert Goldman]

I have always used ASDF:*CENTRAL-REGISTRY*, with some local code that
grovels over source trees.

I'd love to stop maintaining the tree groveler, and move to the DSL, but
I have never understood how you debug the DSL when ASDF fails to find
your system.

With *CENTRAL-REGISTRY* you pretty much pprint the variable, eyeball it,
and it's usually pretty easy to see whether a directory is missing.

But what do you do if you use the DSL?  The last time I tried to use the
DSL, I found myself using the inspector to grovel over internal-to-ASDF
hash tables, which wasn't very pleasant.

Is there a "debugger API" to the new source configuration search?  E.g.,
can we dump the hash-table in a human readable (sorted, formatted way?)?
can we trace something to see how ASDF is populating the hash table?

cheers,
r