The object argument specifies the object to enable breaking on logs for.
The type argument specifies the log-type to enable breaking for.
The substr argument can be used to only break on logs which contain this string. Together with the -regexp flag the string is interpreted as a regular expression, as defined by the re module in Python. The -once flag causes the breakpoint to automatically be removed after it has triggered.
If -recursive is used, not only the object, but the objects hierarchically below the object will be considered when adding the breakpoint.