I know CSS Selectors should be generally of the following format:
tagName[attributeName='attributeValue']
For example Ask Question button on stackoverflow.com main page is sitting inside a div
element matching the following CSS selector div[class='d-flex']
However I see with my Chrome DevTools that div[class=d-flex]
locator is matching this element as well and it is found to be a correct locator!
So, my question is why the CSS selector expressions without apostrophes around the attribute values are still found as correct by the DevTools?