This appears to be a log entry from a amateur radio station. Here's a breakdown of the information:

* **04:23**: The time of day.

* **JA3WAZ**: The call sign of the amateur radio operator who is transmitting.

* **on JP-0210(Yodogawa Riverside National Government Park, JP-KY,JP-OS)**: This suggests that JA3WAZ's signal was received at a specific location with the grid square JP-0210, which is likely a geographic identifier. The location itself appears to be Yodogawa Riverside National Government Park in Kyoto Prefecture (JP-KY) and Osaka Prefecture (JP-OS), both of which are in Japan.

* **28074**: This is likely a frequency or mode indicator. In this case, it suggests that JA3WAZ was transmitting on the 28 MHz band using the FT8 digital mode. FT8 is a popular mode for weak signal work and contesting.

So, putting it all together: at 04:23, an amateur radio operator with call sign JA3WAZ was transmitting on 28 MHz (specifically, frequency 28074) using the FT8 mode from Yodogawa Riverside National Government Park in Japan.