Npm install question, node-red-contrib-onvif-nodes

If I run
npm install node-red-contrib-onvif-nodes
then I get version 0.0.1-beta.1, which is to be expected as this is the current version as seen on npmjs.com. However, if I run
npm install node-red-contrib-onvif-nodes@0.0.1-beta.6 as suggested on the node's github page then I apparently get that later version, which is not referenced on npmjs at all. How does that work? Does npm know to go to github to get it?

A subsidiary question, why does that node not appear at all when I search for it in the node-red palette manager?

Hi Colin,
Don't know an answer for the other question, but it doesn't appear in your manage palette because I haven't added the "node-red" keyword in my package.json file. It is not ready for a large audience yet ... And the API might change in the near future, so there might be breaking changes ...

The .1 version has the latest tag, everything since has been published with the beta tag.

If you don't specify otherwise, npm will always install the version tagged latest.

Right, I see, versions visible in the Versions tab on npmjs (not surprisingly).
Thanks.