Fleet-> Your Software Updates will show how battery health lines up with software updates (I'm seeing 1%-2% fluctuation over the last year. Presumably this is a result of rounding issues, temps [about 50F swing], and actual loss).
Charges -> Battery Degradation will show similar data visually (and more granularity)
Note that if your car gets a software update that adds capacity, your summary numbers will be bunk (this will happen with software locked batteries that Tesla unleashes during a disaster situation or odd corner cases like the early 2020 S Long Range (badged) to Long Range Plus)
Where on the TeslaFi website can I find how much my battery has degraded to see if it is below the 70% warranty threshold?
Customer support service by UserEcho