The x-letter has lead to several misunderstandings. I tentatively suggest
Let's remove the LETTER x from the specification and let anyone who feels
that something is missing formulate what they want, using other letters
than x's. It's OK to copy and paste from former e-mails, but do not forget
to consistently replace any occurrence of x with another letter of your
choice, such as a, b, c, or ... w ...
Thus, if someone formulate something for the letter "a" and someone else
formulate something for the letter "c", we know that they are two
different things and we may avoid confusions. Thus we will be able to
write about "a", "c" and "h" without mixing things together.