70mA LED notes: (1) ... The LED is sort of super bright with a built in resistor, so that you can directly apply 5V and get say, 70mA without any problem. If you supply 3V3 the current might be smaller, but might not be much smaller. (2) the built in resistor might be much bigger than 100R, so with or without the series resistor does not make much difference to human eyes. – tlfong01 20 hours ago   
References: (1) Red LED 5mm with Resistor (2V ~ 5V, 2000 ~ 3000 MCD, 620 ~ 625NM) Product Sheet - SparkFun $9/25pcs sparkfun.com/products/14560, (2) YSL-R531R3c-5V Red LED 5mm with Resistor Datasheet - YunSun cdn.sparkfun.com/assets/c/9/b/9/c/YSL-R531R3C-5V.pdf, (3) YSL-R531R3c-5V Red LED 5mm with Resistor Spec - YunSun imgur.com/gallery/GkKqwEo. – tlfong01 19 hours ago...