Schematic set labelled A125F.U together with a SUB PCB section, so the ZIP covers both the main board and the secondary daughterboard; the code follows Samsung phone naming, though the name gives no brand. Sub boards in phones usually carry the charging port and related parts, making this useful for charging and USB faults as well as main board power issues. Open the extracted documents with a PDF viewer and check that the model code and board revision on the device match before relying on part values.
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 @phoneSchematics. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.