As of 02/03/2020, here are the settings:

SEO_SETTINGS = {
    "content_words_number": [300, 600],
    "internal_links": 1,
    "external_links": 1,
    "meta_title_length": [30, 60],
    "meta_description_length": [50, 160],
    "keywords_in_first_words": 50,
    "max_link_depth": 4,
    "max_url_length": 70,
}

A problem is raised if content text is less than 300 words long, a warning is raised if the content is more than 300 words long and less than 600 words long.

A success is raised if content text is longer than 600 words long.

A problem is raised if there is less than 1 internal link on the content (not nav/header/footer).

A success is raised if there is at least 1 internal link on the content.

A problem is raised if there is less than 1 external link on the content (not nav/header/footer).

A success is raised if there is at least 1 external link on the content.

A problem is raised if the meta title tag content is less than 30 chars long, or if it is more than 60 chars long.

A success is raised if the meta title tag content is between 30 & 60 chars long.

A problem is raised if the meta description tag content is less than 50 chars long, or if it is more than 160 chars long.

A success is raised if the meta description tag content is between 50 & 160 chars long.

A problem is raised if there is no keyword in the first 50 words of the content (not nav/header/footer).

A success is raised otherwise.

A problem is raised if the link have more than 4 levels (mywebsite.ext/en/blog/article/ have 4 levels).

A success is raised otherwise.

A problem is raised if the url is longer than 70 chars (without https://).

A success is raised otherwise.