1) documentation: logger_level says "logging level; the log file will be found on /data/logs/default.log following logging levels are available: DEBUG, INFO, NOTICE, WARNING, ERROR, NONE use this for troubleshooting on updating feeds (but be aware that the log file can become very large)"
This is ok, but which of those is the default if nothing is specified?

2) I've changed various levels, but i can't see any appreciable change between DEBUG and any other level

3) Sample log (ERROR level):
"04-10-13 22:24:08 Error error loading feed content: This XML document is invalid, likely due to invalid characters. XML error: Reserved XML Name at line 1, column 38"
How can i understand which feed caused this error? There is no such info!

4) In sources section i can see the red error message, but only if i open the specified feed. It's no possible to highlight a feed if contains errors?