Component Query is described in-depth within the Ext JS documentation, but

goes to
https://docs.sencha.com/extjs/6.5.3/...nentQuery.html

7.0.0 modern would be better
https://docs.sencha.com/extjs/7.0.0/...nentQuery.html

same problem with other links
"when you look at the docs for Grid or ComboBox, you'll notice"

Maybe visitors to documents could say what extjs/? version, modern/classic, etc. they have at the top of the page, or when logged in, to personalize the results.