[paranoiacblack]

Have you actually read the PHP documentation page for nl2br? People are absolutely using it that way and not making any remark about safety or security. As an anecdote, when I started using PHP, I began to use nl2br to change the newlines in my HTML to <br> tags and output them. You can mark that up to me being a bad developer I guess but I literally got the idea from the PHP manual.

Also, your criticism of map() is kind of childish. It doesn't imply to a new learner that they will draw a map, nor does the documentation even hint at anything like that. In the Python documentation, they are given a clear use case and, if they are familiar with programming (or linguistics), understand that usage of the word map as a verb. Don't be obtuse about PHP's bad documentation.