How can I download a tarball (tar.gz) of libecbufr?

A source tarball can be downloaded for any bazaar revision from the web interface.

Go to https://code.launchpad.net/libecbufr and click on the latest commit number (e.g. 286) for the branch you wish to download. If unsure of which branch you want, choose "trunk". This will lead you to a page with a "download tarball" link near the top of the page.