FCC filings such as these usually surface right before a phone becomes official. Since the Pixel 4a is expected to arrive imminently and will likely be positioned as a budget device, one can assume the G025J device is in fact the Pixel 4a.
The filing indicates a Google “G025J” phone can now be sold in the US. The phone doesn't appear to feature radar tech using millimetre-wave radio frequencies, so it likely lacks Google’s Soli radar sensor chip for gesture controls.
There have been questions about whether the Pixel 4a would have that chip, or if Google would cut it to bring down the price of the phone.