Considering how often the Pixel 4a has leaked, you'd be forgiven for thinking that it had already been officially announced and launched. Even Verizon seems to think that the Pixel 4a is available to consumers.
Verizon has posted a changelog for an update to the Pixel 3 XL that includes a mention of the Pixel 4a (via Droid-Life). It's in reference to the car crash detection feature of Google's Personal Safety app that's becoming available to the Pixel 3 and 3 XL with an update this month.
"Today, this feature is already available on Pixel 4s in the US, UK, and AU with primary device language set to English for users who opt-in. In June 2020, this feature will be newly available to Pixel 3 and Pixel 4a users (Pixel 3a is not supported) in the same countries and languages," Verizon says.
Rumors have said that Google was planning to launch the Pixel 4a in late May and then early June before pushing it back to July, so it's possible that Verizon created this support document while the Pixel 4a was still slated to launch this month and then forgot to remove the reference to the 4a.
The most recent reports have suggested that the Pixel 4a is now set to launch on July 13.