The changelog is available as CHANGES.txt in the SCM repository.

Read-only Access

Read-only repository access is provided through

hg clone roundup-code

The URL for the webinterface works, too, but you will see messages about redirects to the URL shown here.

Read-write Access

The read/write access uses your ssh password or ssh key to authorize your access. (See SF’s site documentation on Mercurial access)

hg clone ssh:// roundup-code

Of course a roundup developer must have granted you write access first - ask for it on the roundup-devel list.