I am going to sell my Nexus 5 and did a clean install. However I forgot to add the GApps img to it and now I have no apps on the phone to transfer the file to the root directory nor I can download them as there is no Play Store. The ADB sideload is supposed to flash .zip files and the GApps I found on this thread is called "radio-hammerhead-m8974a-188.8.131.52.30.img" - can I just zip this file and do the sideload?
edit: I'm dumb. WIth some more reading I figured out I could go to opengapps.org and make my own GApps zip file which I could transfer to the device using adb push and install it as a regular file to be flashed.
If you are sellling, why aren't you removing TWRP?