The description of log_warnings incorrectly mentions the "general log":

static Sys_var_ulong Sys_log_warnings(

       "log_warnings",

       "Log some not critical warnings to the general log file."

       "Value can be between 0 and 11. Higher values mean more verbosity",

       SESSION_VAR(log_warnings),

       CMD_LINE(OPT_ARG, 'W'),

       VALID_RANGE(0, UINT_MAX), DEFAULT(2), BLOCK_SIZE(1));

https://github.com/MariaDB/server/blob/mariadb-10.3.35/sql/sys_vars.cc#L1373

The "general log" is most likely to refer to the "general query log", but this log is not affected by log_warnings. Instead, log_warnings affects the error log.

The message should probably be edited to say something like this:

Log some non-critical warnings to the error log. Meaningful values are between 0 and 11, where higher values mean more verbosity. Values between 11 and UNIT_MAX are equivalent to 11.