Copyright of icons is as followes:

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datacenter.png, lamp.png, factory.png, datacenterred.png, lampred.png, factoryred.png,   

Taken from MS Word

According to https://support.microsoft.com/en-us/office/insert-icons-in-microsoft-office-e2459f17-3996-4795-996e-b9a13486fa79 (date: October 9th, 2019)
"These icons are free to use; there's no royalty or copyright."