The recently added flags in timescale/promscale#578 are yet to be updated in prom-migrator's readme which can be found here.

While executing this query on Quantum :

$RTOKEN 
<' 
select(*) 
'>
TSL

I encountered this error :

ERROR line #9: Exception at '=>TSL<=' in section [TOP] (Line #4 (Exception at '[ 'token' =>~.*<= {} ] FIND' in section [TOP] (Unknown function '~.*')))

This should work as indicated here : https://github.com/ovh/tsl/blob/master/spec/doc.md#select

https://twitter.com/roidelapluie/status/1363428376162295811?s=19