Can you post links to those articles? What were the keys supposed to do? Can you find the symbol in Character Viewer? If so, you can post it here.
Another thought: Look at Keyboard Viewer to see if that symbol appears there.
Jon
macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P700, Photoshop CC, Lightroom CC, MS Office 365
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