Yesterday, T-Mobile told us to expect monthly security updates for Nexus devices including the Nexus 4, 5, 6, 7 (2013), 9, and 10. Today, Google posted the factory images for each as build LMY48M.
Keep in mind that the T-Mobile Nexus 6 will receive a different update as build LYZ28K, so if you are running a Nexus 6 on T-Mo, don’t flash these LMY48M images.
Update: Factory images for the Nexus 6 on T-Mobile (listed as LYZ28K) and Project Fi (listed as LVY48F) have been uploaded. The factory image for the Nexus 7 (2013) LTE (listed as LMY48P) has also been uploaded.