Retrieve long text string containing semi-formatted (simple text with newlines and spaces for indentation) SquirrelMail system specs

• return: A three-element array, the first element containing the string of system specs, the second one containing a list of any warnings that may have occurred, keyed by a warning "type" (which is used to key the corrections array next), and the third element of which is a list of sub-arrays keyed by warning "type": the sub-arrays are lists of correction messages associated with the warnings. The second and third return elements may be empty arrays if no warnings were found.
• since: 1.5.2