https://www.ebay.com/itm/404204890868

No clue.

• SMA female for GNSS Ant
• 10/100 RJ45
• DC 5V input (5.5mm/2.1mm) - Marked 1A, but I haven't measured the device pulling more than 200mA

• One button: Marked SW-PB, pulls the 3v3 rail of the LDO to ground through a 10k resistor
• One LED: red power LED hanging off 3v3 thru 1k resistor
• Red TX/RX LEDs on the UART-RS485 board

• JP10 - 1×3 - GND | Pin 18 of GNSS (reserved???) | Pin ## on MCU - unpopulated
• JP1 - 1×4 - R/T | R/T | GND | 3v3 - populated - suspected MCU UART
• JPB - 2×3. First row is marked 5 on the left side, second row is marked 6. Right pins are marked 1 and 2, top and bottom, respectively. Middle pins are presumably 3 and 4, top and bottom. Pins 1 & 2 are 3v3. Pins 5 & 6 are GND. One jumper is present bridging “3” and 5. Unknown what “3” and “4” connect to.

• GNSS - AT6558 R-5N-32-E2 based, likely ATGM336H5N-31? - No silkscreen mark - maybe underneath?
• MCU - CH32F103 - STM32 “bluepill” clone - Marked T32
• NUC - WIZNet W5500 10/100 SPI - Marked U5
• EEPROM - FT24C16A 16Kbit i2c - Marked IC15
• ?????? - R8025 E R41 72 - Marked RX1
• 3v3 LDO - AMS1117 3.3 - Marked U1
• UART to RS485 module mounted on board - Marked T4

• Entirely hand-assembled
• Small heatsinks mounted to the GNSS, MCU, and NIC - absolutely not needed
• OLED screen mounted perpendicular to the board via a female header sitting flat is very clever!