In Canonization, Google tries to combine URLs as one URL when it thinks there may be duplicate URLs. How Google does this can depend on many different signals. Google's John Mueller listed some of the signals that Google uses for canonicalization.
John posted the following list of signals Google uses for canonicalization on Twitter:
- External links
- Canonicals tags
- cleaner urls or shorter urls
- and more…
Here is John's tweet:
Redirects are a signal for canonicalization, but they're not the only ones. Internal, external links, sitemaps, hreflang, canonicals, cleaner URLs, etc. play a role. Line everything up, give him time to settle down, and leave cookies and almond milk for googlebot.
– 🍌 John 🍌 (@JohnMu) July 31, 2020
Forum discussion on Twitter.