ROMs How does the qemud service of emulator works

[netants999]

AOSP12
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04-15 21:46:08.170 I/lowmemorykiller( 166): Using psi monitors for memory pressure detection
04-15 21:46:08.171 I/lowmemorykiller( 166): Process polling is supported
04-15 21:46:08.184 I/qemu-props( 170): connected to 'boot-properties' qemud service.
04-15 21:46:08.185 I/qemu-props( 170): receiving..
04-15 21:46:08.185 I/qemu-props( 170): received: ro.opengles.version=196608
04-15 21:46:08.185 I/qemu-props( 170): ignoring 'ro.opengles.version' property
04-15 21:46:08.185 I/qemu-props( 170): receiving..
04-15 21:46:08.185 I/qemu-props( 170): received: qemu.sf.fake_camera=both
04-15 21:46:08.187 I/qemu-props( 170): successfully set property 'vendor.qemu.sf.fake_camera' to 'both'
04-15 21:46:08.187 I/qemu-props( 170): receiving..
04-15 21:46:08.187 I/qemu-props( 170): received: dalvik.vm.heapsize=512m
04-15 21:46:08.187 I/qemu-props( 170): ignoring 'dalvik.vm.heapsize' property
04-15 21:46:08.187 I/qemu-props( 170): receiving..
04-15 21:46:08.187 I/qemu-props( 170): received: qemu.hw.mainkeys=0
04-15 21:46:08.187 I/qemu-props( 170): successfully set property 'qemu.hw.mainkeys' to '0'
04-15 21:46:08.187 I/qemu-props( 170): receiving..
04-15 21:46:08.187 I/qemu-props( 170): received: qemu.sf.lcd_density=560
04-15 21:46:08.187 I/qemu-props( 170): successfully set property 'qemu.sf.lcd_density' to '560'
04-15 21:46:08.187 I/qemu-props( 170): receiving..
04-15 21:46:08.187 I/qemu-props( 170): received: net.wifi_mac_prefix=5554
04-15 21:46:08.188 I/qemu-props( 170): successfully set property 'vendor.net.wifi_mac_prefix' to '5554'
04-15 21:46:08.188 I/qemu-props( 170): receiving..
04-15 21:46:08.188 I/qemu-props( 170): received: qemu.timezone=America/Los_Angeles
04-15 21:46:08.188 I/qemu-props( 170): successfully set property 'vendor.qemu.timezone' to 'America/Los_Angeles'
04-15 21:46:08.188 I/qemu-props( 170): receiving..


When I boot the emulator, I get the above log in aosp 12. I wanted to know where in the code this attribute(qemu.sf.fake_camera) was read from and sent from qemud service process to qemu-props process. I looked for it in the aosp code for a long time, but I couldn't find it. I would appreciate it very much if you have some knowledge of the simulator.