Proposal to add a browsing context named "_private"

Hi all,

Most browsers now have a private browsing mode, which offer similar
features, i.e. browsing history is not recorded, cookies are not saved,
localstorage is flushed when the context ends, and some other forms of
isolation.

I think it would make sense to formalize such a browsing context and allow
a webpage to specify that the "target" for an <a> link is "_private", so
that the page opens in private mode. I can imagine several use-cases for
this, ranging from aggregator sites offering a privacy preserving browsing
mode to developers using it for maintaining two sessions on apps they are
developing. For example, Reddit may offer a mode in which all NSFW links
automatically open in private mode. Several browser extensions/addons
(including one by me) have been developed to "work-around" this problem and
I think that the browser itself is the best place to remedy the issue.

Does this make sense or are there better alternatives/previous proposals
which deal with this?

I had initially posted this here: https://github.com/whatwg/html/issues/493
and Anne recommended running it by this mailling list to see if there is
any interest in it.

Thanks!

~
ut