List of currently assigned browser labels
Browser labels are an easy way to identify locations you are and were logged in from.
They give you the ability to tag a certain browser with your own custom name, so that instead of the Browser + IP pair the Active sessions and the Activity logs pages could display your custom name instead.
Be aware that this system uses cookies to identify browsers so clearing them will effectively be deleting your label for the affected browser. There is no way of knowing when something like this happens, so the label will be stuck until you delete it yourself.
This page lists all the browser labels you have created.
You can delete and edit them here, but in order to add them you have to go to the Active sessions page and click the "Add label" link on one of the sessions there.