The Google Play Developer Console has posted information for the "sargo" and "bonito", which are the codenames for the Pixel 3a and Pixel 3a XL, respectively. As noted by Reddit user ElegyD, the "sargo" is listed as having 4GB of RAM and a 2220x1080 display with a pixel density of 440, while the "bonito" has a 2160x1080 display with a pixel density of 400 and 4GB of RAM. Both phones come with Android 9 Pie.
Given this information, it's likely that the Pixel 3a "sargo" has a display that's around 5.6 inches while the Pixel 3a XL "bonito" has a screen that measures around 6 inches. These displays are expected to be of the OLED variety. Other rumored Pixel 3a specs include a Snapdragon 670 processor, 12MP rear camera, and 3000mAh battery.
One other detail worth noting is that in the "system features" section, the phones are listed as having "PIXEL_2019_MIDYEAR_EXPERIENCE". That suggests that these phones will arrive sometime in the middle of 2019. A previous rumor had pegged the two phones as launching on Verizon sometime this spring.
The big pieces of information that we're still missing for both the Pixel 3a and Pixel 3a XL are their prices. These are expected to be lower-cost versions of the flagship Pixel 3 and Pixel 3 XL, so pricing is kind of important. If these devices are indeed coming this spring, hopefully we'll hear more about them soon.
Are you interested in the Pixel 3a or Pixel 3a XL?