While your are correct in charging methods, for the rating they just refer to it as C.
for those more interested in the topic: https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
Now the caveat is, that is for cobalt blended batteries which are the more common Li-ion you will find, however in recent years most manufactures are switching to Li-ion chemistries that have no cobalt. While i don't know the specifics of how that affects the charge times I do wonder what effects it has.