(Actually this looks bad on the wiki even.)

I think it might be better to just not try to have that inline. The line is long enough that it should probably be in a separate block. You can also work around the vagaries of the formatting this way:

....
%global __os_install_post %(echo '%{__os_install_post}' | sed -e 's!/usr/lib[^[:space:]]*/brp-python-bytecompile[[:space:]].*$!!g')
....

The four dots delimit a literal block. (You can use four or more dots, as long as you use the same number at the beginning and the end.) You can also do

[literal]
%global __os_install_post %(echo '%{__os_install_post}' | sed -e 's!/usr/lib[^[:space:]]*/brp-python-bytecompile[[:space:]].*$!!g')

if the text doesn't include any blank lines. See https://asciidoctor.org/docs/user-manual/#delimited-blocks

But... if this is F27 only, why don't we just remove it? F27 is EOL, after all, and so we should generally work towards removing F27-only things from the pages.

I was thinking EPEL. But we can certainly remove that information altogether or move it to EPEL guidelines.

Well, I guess this is the appendix. So why not at least just fix it. I'll merge and then edit the "Fedora 27" to "EPEL7" so that this won't show up when grepping for old stuff that needs updating.