Explanation
The Code Reference is a new version of the Codex that implemented one important change: it's auto-generated instead of waiting for manual user entry. How it does so is by reading the comments in the code of WordPress itself. This makes it a more reliable resource for researching any code or code-related topics like functions, classes, or hooks. However, one could argue the Codex is better since auto-generation could leave out more in-depth content. Any documentation on the Codex is the result of many users' writing styles and experiments.
the_date()
the_date returned the date that a post was published on. If a post was never fully published, the function will return the current date. However, if posts are looped through like on the main page for this class, it will only display one date per every day that the posts fall under. Finally, it's different from get_the_date because it outputs HTML instead of a string.
the_date() Parameters
- format: specify the format of the date output. This can be any values, any order, and any combination of symbols since the only thing the method cares about being specified in the string is the letters that represent the different date values.
- before: an easy way to concatenate other values before the date display.
- after: an easy way to concatenate other values after the date display.
- display: true if you want to echo the value. False if you just want to return it.
Summary
Overall, the Code Reference seems like the more useful version of documentation, but I don't think it matters anyway since Codex entries seem to be included at the bottom of the page. Also, the_date seems more useful than get_the_date since you're working with a lot of HTML in website coding.