Apple iPhone 5S boardview, .bvr format, 254 KB. The name does not say which regional or radio variant it covers, and a separate WCDMA-labelled layout exists, so check the radio section of your board against this one before probing there. The file shows component placement and nets, letting a technician search for a part, see which pins share a rail and choose test points. It supports common repairs such as locating a short on the battery line, tracing the charging path and checking display or touch connector signals.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @SMART_PHONE_SCHEMATICS. Enginerys does not host this file.
How to open a .bvr file
Text boardview from the BoardView R family of tools, seen for Lenovo, MSI and Clevo boards.