Basically, just upload the thing, and document whether you want other people's extensions to live under the root namespace or somewhere else - e.g. DBIx::Class extensions are mostly just under DBIx::Class:: whereas Moose extensions live in MooseX:: - and a hybrid would be Catalyst, where certain types of extensions live under e.g. ::Plugin::, ::Model::, etc. and then things that don't fit in any of the usual extension namespaces go into CatalystX::

You'll find, generally, that people writing an extension to your code will respect your choices, and that any violation of them will usually be an accident and quickly resolved by filing a bug saying "hey, could you follow the policy please".

I did, honestly, mean to email you off list explaining what was likely to happen wrt the registered module list (starting a thread about it at the time on modules@ would likely have been ... unproductive).

Unfortunately, I completely forgot, a failure for which I'm hoping my responses to you today will at least partially compensate :)