Every icon tells a story
If a regulatory standard does not have a publicly accessible database to confirm conformance, it is useless. This includes the worst such standard of all: the self-certified. See also Ethernet over powerline, RFI, and Ofcom.
Most of these back/bottom certification marks don't represent information about whether the product does what it's supposed to. Instead, they tell you about aspects of the device's safe operation or environmental/ecological product manufacture/return lifecycle.
For example, electrical products to be sold in North America require a safety mark from OSHA-approved Nationally Recognized Testing Laboratory (NRTL) -- meaning an organization that's authorized and qualified (and audited) to perform the tests specified in the standard. Having this certification mark assures the buyer/user that the device is electrically safe to use, (i.e, when you plug it in and turn it on, it won't electrocute you, go up in flames, etc.).
Some certification marks indicate what kinds of physical and environmental abuse the device can tolerate. For example, the U.S. government's MIL-STD-801G standard lists over a dozen types of "ruggedness" testing, (e.g., being dropped from three or six feet, how much heat or cold or "thermal shock" going suddenly from one to the other, humidity, fungus, altitude, vibration, etc. -- the lab facilities for testing these are interesting places.) IP (Ingress Protection) Rating marks indicate how much protection the case provides against physical objects (fingers, screwdrivers, dirt, sand, etc.) and liquids (rain, cleaning fluids).