This information was reported by Jon Prosser, a prominent leak account. According to his tweets, there's a 100% chance that the Pixel 4a will be introduced on August 3. He has a track record of providing accurate information about the iPhone SE (2nd generation) as well, which is worth noting, even if it's not official.
Furthermore, a device that looks like the Pixel 4a has been found registered on the benchmarking app Geekbench.
The registered device information states that the processor is equivalent to the Snapdragon 730 and has 6GB of RAM. The score also appears to be a mid-range equivalent device with a single core: 551/multi-core: 1655.
This article is based on an article from the Japanese edition of Engadget and was created using the translation tool Deepl. The Japanese edition of Engadget does not guarantee the accuracy or reliability of this article.