BNF of text/gemini

Here's the BNF (based on RFC-5234) of text/gemini, as it is probably produced today.

        textgemini  = *(link / preformat / heading / ulist / quoted / plain)
                        ; Preformat toggle starts as 'false'.

        plain       = text end-of-line
                        ; If preformat toggle is false, wrap text to the
                        ; width of the display.  Otherwise, do no wrapping.

        preformat   = "```" [alt-text] end-of-line
                        ; Preformat toggle set to opposite state:
                        ;       false goes to true
                        ;       true goes to false
                        ; While in preformat toggle is true, link, heading,
                        ; ulist and quoted lines are NOT interpreted, but
                        ; displayed as is to the user.

        link        = '=>' [SP] URI-reference [SP text] end-of-line

        heading     = '#'   SP text end-of-line
                    / '##'  text end-of-line
                    / '###' text end-of-line

        ulist       = '*'   SP text end-of-line

        quoted      = '>'   text end-of-line

        alt-text    = text
        text        = *(UVCHAR / WSP)
        end-of-line = [CR] LF

        UVCHAR   = VCHAR / UTF8-2v / UTF8-3 / UTF8-4
        UTF8-2v  = %xC2 %xA0-BF UTF8-tail ; no C1 control set
                 / %xC3-DF UTF8-tail

; CRLF          from RFC-5234
; DIGIT         from RFC-5234
; SP            from RFC-5234
; VCHAR         from RFC-5234
; OCTET         from RFC-5234
; WSP           from RFC-5234
;
; UTF8-3        from RFC-3629
; UTF8-4        from RFC-3629
; UTF8-tail     from RFC-3629

The only possible breaking change is disallowing the C1 control set (ANSI terminal sequences) as there are sites out there that use them to set various colors.