The 20 V rating gives comfortable headroom on a 12 V rail — a 10 V cap would be marginal on a 5 V rail with a 20 % tolerance supply, but 20 V covers a 12 V bus with margin for the transient.
1.6 Ohm ESR and the ripple budget
On a 100 kHz buck converter output, the ripple current through this cap should stay under the manufacturer's ripple current rating — exceeding it raises the internal temperature above the 125 °C ceiling and accelerates wear-out. For a low-ripple linear regulator output, the ESR is less of a constraint.
Active — no last-time-buy window
This cap is still a production part — no need to stockpile or find a second source yet.
Molded case, size code C, -55 to 125 °C
Molded case, size code C (6.00 mm x 3.20 mm footprint, 2.80 mm seated height).