Another example for the Sylpheed mailing list (not claws!) is:
\[sylpheed:[0-9]{5}\]
+* new cache
+ New cache is a new data cache structure for sylpheed, that will
+ solve many of the problems sylpheed currently has with updates to
+ flags. But you will also notice a large speed gain when you open
+ these folders.
+
+ New cache uses two new configuration parameters that can be
+ adjusted in ~/.sylpheed/sylpheedrc (no gui for them available yet).
+
+ cache_max_mem_usage (default: 4096)
+ the maximum kB of memory sylpheed should use.
+ It will try to keep the memory usage below this
+ value, but it will always use the assigned
+ amount of memory for speed gain.
+
+ cache_min_keep_time (default: 15)
+ the minimum time in minutes sylpheed will keep
+ the folder cache in memory. If a cache is more
+ recent than this time it will not be freed even
+ if the memory usage is above the maximum. You
+ should probably set this value higher than your
+ mail check interval. Otherwise the cache will
+ always be freed between checks even if the folder
+ is accessed on every check, which will cause much
+ disk IO.
+
+ The check if memory can be freed is currently done after the
+ active folder has been changed or whenever a new cache is read,
+ i.e. triggered by mail incorporation.
+
+ New mails in MH folders are not detected automatically like before,
+ when you enter the folder. You have to update the folder manually,
+ or activate the auto update setting in the options.
+
There are a lot more options. If you find one, don't hesitate to
mention it.