That's a great find.
Maybe @Dennis Alwon will add it to his Resources directory.
On the first entry, what they call NEMA capacitor symbol is what the electronics industry uses for Electrolytic Capacitor.
What they call IEC capacitor is what we use for Ceramic Chip Capacitor, so at times we see both symbols on a plan.
Specifically, Texas Instruments does it this way and it makes it easy to see an application design to know what's involved without digging up the part numbers and looking up the parts.
For me, I prefer to avoid the electrolytic caps due to their history of failure (think Dell computer motherboards in the 1990's and forward).
With today's modern buck converters we can buck 24VDC down to 3.3VDC with only ceramic chip caps and an inductor, with very low ripple and nearly 90% efficiency.