Right now, we're claiming to support:

The option about market share is completely useless, per the algorithm, this is the last 4 versions of any browser, or a Firefox ESR, but not old IEs.

If we wanted to reduce the list of supported browsers according to market share, it'd need to be a

'not <1%'

but that excludes any version of Firefox or IE that by itself doesn't have that market share, including ESR, http://browserl.ist/?q=last+4+versions%2C+Firefox+ESR%2C+not+ie+%3C+9%2C+not+%3C1%25.

My suspicion is that our list was intended to be "of all the browsers with at least 1% market share, support the last 4 versions, IE aside". Such a query doesn't exist, sadly.

The only way we could emulate that is to manually maintain the list of browsers we support, and then restrict to the last 4 versions, or so.