Values
Critical errors, software module can not recover on its own.
Error conditions from which recovery measures have been taken.
Information messages which describe normal flow of events.
Extra information which is not necessary for normal use (values, pointers, sizes, etc).
Bigger chunks of debugging information, or frequent messages which can potentially flood the output.
Number of levels supported.
Examples
esp_log_level_t is referenced by 5 libraries and example projects: