Raspberry Pi One Kernel missing from Alpine 3.9.3 (armhf)

The official release of Alpine 3.9.3 for armhf is missing the kernel and initrd for the original Raspberry Pi model B.

Config.txt correctly lists:

[pi1]
kernel=boot/vmlinuz-rpi
initramfs boot/initramfs-rpi

But all the required files are missing from boot/.

(from redmine: issue id 10407, created on 2019-05-07)

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