Battery Recall for 15-inch MacBook Pro Retina mid-2015. Check Apple’s site for recalls, and put in your serial number. They replaced my swelling battery for free, regardless of warranty.
Here’s a GDoc that has a photo of the starting point for lifting the midframe out:
Here’s a series of GDocs that have pictures of the locations and descriptions of the 20 snap-tabs that hold the back cover on.
Here’s a photo of the location of the 20 tabs that hold the middle assembly in place, and the pry angle needed.
Here’s a photo of the location of the 18 tabs that hold the back cover in place
Reassembly: Before slipping the main frame back into its place, refer to earlier photos, ensuring proper routing of the WiFi cable.