After a brief delay, google has now posted Pixel 6 lineup OTA packages and factory images for the March security update and Feature Drop. We're not seeing anywhere that Google specifically mentions what caused the delay, but here we are.
The rest of the Pixel lineups received this same update on March 13. Inside, you'll find the security patch (what's new here), plus the latest features thanks to the Feature Drop (what's new here). Below you'll see the updated build numbers for Pixel 6, Pixel 6 Pro, and Pixel 6a.
- Pixel 6: TQ2A.230305.008.E1
- Pixel 6 Pro: TQ2A.230305.008.E1
- Pixel 6a: TQ2A.230305.008.E1
Google should begin pushing these updates shortly over-the-air (Settings>System>System update), but if you don't want to wait for Google and prefer to update manually, you will find each factory image or OTA file at the links below. For instructions on how to flash a factory image, here you go. For instructions on how to flash an OTA .zip file, here you go.
// Google Support