Almost caught: the file is this openwrt-packages-yun/wifi-live-or-reset at master · arduino/openwrt-packages-yun · GitHub
when the yun starts, it expects wifi to work withing 60 seconds. "work" means either it was able to connect to your home wifi or its own access point was set up. During these 60 seconds, the wland led blinks
If you want to disable wifi Arduino Playground - Yun