Lenovo Tab 3 Essential tablet archive, 3.02 MB in ZIP format. The file name lists only the product line, so the exact contents and the specific model variant are not stated. Packages like this usually contain schematics or service diagrams used to trace the power supply from the battery connector, check the charging circuit, locate display and touch connectors and find measuring points on the board. Extract the files first and review them. Because several variants exist under this name, check the model code and board marking on your unit against the documents.
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 @esquematicosparatodos. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.