The Terminal Block Featherwing doesn't have any active components. Instead, it just breaks out all the existing connections from a Feather. Note that Feathers use different chipsets so not all pins are labeled on purpose!

The only pins you can depend on are:

• 3.3V power
• 3.3V enable
• VBat power
• USB power
• GND
• Reset
• I2C: SDA & SCL
• SPI: MOSI, MISO, SCK
• UART: RX & TX

Check your Feather documentation and product page for details on what other pins are available and what they are connected to