Bootloader information?

Is there any way to find out what bootloader an Arduino Uno is running, or if there's an official newer one?

The changelogs for the Arduino software make it sound like there are updates sometimes but it's not clear if there are, and if there's any way to tell if it even matters. I've read some things about lockups or watchdog timers fixed by bootloader changes but nothing saying how to know what I have or decide what I should do.