date_end liquid variable?

[kuopaz]

This gives you the ending date in a date filter, and is very useful.

If the user selects ‘is in the past 1 complete months’ for today (9 July), date_end seems to return 1 July, whereas I was expecting date_end to return 30 June.. This may be consist in Looker (‘ is in range’ means putting 1 June to before 1 July),  but there is a serious risk of getting tripped-up.

Am I correct in what I have said in the above? And couldn’t it be explicitly documented (haven’t been able to find it).