Hopefully everyone knows about the xlist command. It returns the object type, layer, color, and linetype of an entity that is in either a block or an external reference drawing. Sometimes the resulting dialog box isn't large enough to read the layer name so give this a try:
This command will give you the same information, but the result appears in the command line instead of a dialog box. It's also helpful when you're trying to find a layer in a layer list to either change the color, lineweight, or plot style. By having the results in the command line, you can still read the layer name while your browsing through the layer manager list.