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Some older laptops with Lithium Ion batteries adopted the charge to "100%" and don't charge again unless below a certain trip point, usually 90 or 95%... My 2008 or so vintage Lenovo X200T displays this behavior because of Lenovo's additional software despite having been updated to Windows 10. Never saw any harm in it as Lenovo may have simply been hedging their bets or noted a possibility that they'd set too high a limit in the hardware cutoff of their design, or just found that rapid cycling due to the laptop being plugged in was causing heating and lessening battery cycle life, etc...
It's quite likely that most competent engineers will leave a little headroom if they're defining the cutoff points in software or hardware rather relying on a third party hardware solution, and even most of them seem to stop just a bit short of the battery manufacturer's specs which are likely a tad conservative as well. Safe, rational engineering at multiple levels often saves even the reckless engineer's ass when they "get a little nuts"!
Any well designed piece of equipment will allow charging to near the battery's high end, but not exceed it for danger of explosion, meltdown, etc. Most modern lithium packs have built-in low & high end cutoff circuits, I've even added them to individual Lithium Ion 18650 cells used in my LED flashlights for discharge protection, but there may be a few products still floating around without them.
PS. It can be a little disconcerting with these protection circuits/cutoffs built into flashlight batteries, as they can suddenly shut off to prevent too high a current or too low a voltage. But I mostly keep them well charged, and employ a spare or spares as may be needed. The nice part is they also prevent short circuit and you can reasonably safely toss a protected battery in your pocket without worrying about change, etc. shorting it and causing a thermal meltdown. They also allow me to easily carry a spare protected 14500 battery which fits my pocket everyday carry LED flashlight with adjustable power levels, dazzler function and beam width/focus. Yeah, I know, but it throws a focused beam my phone can't, fits in my mouth when I need both hands, and I often don't carry my Kobo Glo around outside at night! ;-)
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