Archive linked to the Apple logic board 820-00239, a number following Apple's 820 prefix scheme for logic boards. The name says nothing of its contents, so it may contain schematics, boardview data or firmware, and should be inspected after extraction. Material of this kind is used to trace power rails, locate components and check for shorts on MacBook boards. Match the 820 number printed on the logic board before relying on any of the files inside the 6.17 MB zip.
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 @schematicslaptop. Enginerys does not host this file.
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Built-in OS tools7-Zip