Wordpress uses the 'external nofollow' value for rel attribute. It's a lazy way of putting nofollow for all links where only external links are nofollowed
Hello, "nofollow" is used for managing the link value flow within the website (not sending a lot of juice to a contact us page or something like that), while "external nofollow" is used to tell the Search engine bots not to index "outbound links", which are links going to other websites.
There's a Wordpress plugin that will allow you to dofollow your links easily. You can turn it off or on.
nofollow = all external and internal links are nofollow external nofollow = only external links are nofollow.