Currently, the Info node about effort estimates does not mention what format should it be written in. This causes confusion, as a user might assume that it's the same format as schedulers (10m, 6h, etc.) like I did.
Simply mentioning "Effort estimates need to have the format H:MM" (copied from the docstring or org-effort-property, the only* description of the format I could find) in the Info node would be enough. *: searching for regexp effort.*format and manually filtering out the other 3 matches
