Refine: Midpoint rooting without timetree?

Is it possible to midpoint root a tree with refine without having time metadata available?

The docs for refine refer to treetime which states:

–reroot REROOT [REROOT …]
Reroot the tree using root-to-tip regression.
Valid choices are ‘min_dev’, ‘least-squares’, and ‘oldest’.
‘least-squares’ adjusts the root to minimize residuals of the root-to-tip vs sampling time regression, ‘min_dev’ minimizes variance of root-to-tip distances.
‘least-squares’ can be combined with --covariation to account for shared ancestry.
Alternatively, you can specify a node name or a list of node names to be used as outgroup or use ‘oldest’ to reroot to the oldest node. By default, TreeTime will reroot using ‘least-squares’. Use --keep-root to keep the current root.

I’m not quite sure how to interpret the options. It may also be a good idea to include this help text directly in refine help to have less indirection for users.

The reason I’m trying to midpoint root is that I just quickly want to build a tree and don’t want to bother with time metadata, just work off sequences.

min_dev should do this in principle (a variant of mid-point rooting). But I am not sure the plumbing is such that it can be used without timetree.

currently augur refine can’t root at midpoint without a time tree. but there is no reason why not.