This is not a specific software "feature" but rather a technical request often used in automotive, HVAC, and industrial forums to find wiring instructions for specific devices. Common examples include:
The phrase is a transliterated shorthand for "эл. схема подключения" (el. shema podkljucheniya), which translates from Russian/Ukrainian to "electrical connection diagram."
Standard icons for capacitors, relays, motors, and fuses.
Labels like BN (Brown), BU (Blue), or G/Y (Green/Yellow) to identify physical wiring.
Wires connecting a remote control or a secondary unit.
Wiring the indoor and outdoor units to the power grid.