Generated feed does not validate on validator.w3c.org

[Dovizu]

Discovered this issue while looking into another issue. An example: https://validator.w3.org/feed/check.cgi?url=b-side.donny.io%2Ffeed.xml

[ashmaroli]

Based on the validation report, the errors seem to be because of en_US set as lang attribute.
This is actually defined in your config file.
Therefore, edit your config file to:

_config.yml

lang: en
locale: en_US

Consequently, do edit the layouts and includes of your site to reflect the change above.

[Dovizu]

Great, edited the issue and now my feed validates. It was my mistake after all, thanks!