Which proprietary blobs exactly does the Librem 14, running PureOS, include by default?
The Librem 14, running PureOS, includes a few proprietary blobs by default. These include the firmware for the Intel Wireless-AC 9560 card, Intel CPU microcode updates, and the proprietary firmware for the onboard TPM chip.

It's worth noting that Purism, the company behind the Librem line of laptops, has made it a priority to minimize the use of proprietary software and hardware in their products. For example, they have replaced the Intel Management Engine (ME) with the open-source ME_cleaner utility and have also created the PureBoot bundle, which includes a tamper-evident firmware and a trusted platform module (TPM) for added security.