if you have a USB wifi device which uses the ath9k or ath9k_htc kernel module, you should postpone upgrading to any of the 5.7.6 kernels; or the device may not work when you next reboot - PCI devices do not seem to be affected by this bug
watch this bug report for further details
linux-libre and linux-libre-headers 5.7.6 have been pulled from the repos and replaced with 5.7.2; but other kernels remain at 5.7.6 - if you have already upgraded to one of the 5.7.6 kernels, and your wifi does not work, you will need to revert to the previous kernel:
# pacman -Syuu linux-libre
or boot a parabola LiveISO, mount your / partition, and install it with pacstrap:
# mount /dev/sdXN /mnt
# pacstrap /mnt linux-libre