Google uses the hreflang attributes to serve the correct language or regional URL in their search results and many sites that use hreflang have multiple variations of their pages. One webmaster asked if it matters which order you place the hreflang in. So if you place EN before EN-GB does that make any difference to Google?
John Mueller of Google said no, the order of the language values do not make any difference.
He said this on Twitter:
no, order doesn't matter.— John â.o(â§â-½â¦)o.â (@JohnMu) June 7, 2017
Makes sense for it not to matter but first time I saw the question asked and answered.
Forum discussion at Twitter.