Skyrim Special Edition save filenames clearly have useful information in them in a specific format. This information can be handy e.g. when going back through the save game history to decide which saves to keep and which to dump, since a directory full of multi-megabyte saved games can get very large.
Here are some example filenames:
Autosave3_74DD6D56_1_42617469737465_KnifepointRidge01_000521_20171125110855_3_1.ess Quicksave0_74DD6D56_1_42617469737465_KnifepointRidge01_000527_20171125111521_4_1.ess Save1_AC6950AD_1_507269736F6E6572_Tamriel_000006_20171125005247_1_1.ess
What do the various components mean?
Feel free to update the community answer if you have only a little extra information to add.