The latest firmware auto build supports I2C sniffing up to 500kHz via the pico-i2c-sniffer project.
The output is similar to the I2C command syntax. Sniffed packets can be pasted into the command line and replayed.
The q quiet flag hides the ACK (+) indicator to make it easier to replay commands without editing the sniffer output. NAKs (-) will still be displayed.