Technically, nobody lives in "UTC". You might say people live in UTC+0, which is a standard time zone around the prime meridian. UTC refers to the system of standard time zones, not a single time zone, but in common speech "UTC" is often understood to mean UTC+0.
Let's say you live in California. During the winter, you observe PST ("standard time"), which is UTC-8. During the summer, you probably observe PDT ("daylight time"), which is UTC-7. Switching between the two is sort of outside the scope of the UTC system. It happens locally and is subject to local social and political preferences. Digital clocks mostly just keep track of standard time and possibly adjust their output if presenting a human-readable timestamp string.
Leap seconds are very much inside the scope of UTC. A leap second occurs globally for every standard time zone at the exact same global instant. It's determined by an objective criterion based on UT1.
Technically, nobody lives in "UTC". You might say people live in UTC+0, which is a standard time zone around the prime meridian. UTC refers to the system of standard time zones, not a single time zone, but in common speech "UTC" is often understood to mean UTC+0.
Let's say you live in California. During the winter, you observe PST ("standard time"), which is UTC-8. During the summer, you probably observe PDT ("daylight time"), which is UTC-7. Switching between the two is sort of outside the scope of the UTC system. It happens locally and is subject to local social and political preferences. Digital clocks mostly just keep track of standard time and possibly adjust their output if presenting a human-readable timestamp string.
Leap seconds are very much inside the scope of UTC. A leap second occurs globally for every standard time zone at the exact same global instant. It's determined by an objective criterion based on UT1.