metasyntactic variable

Question

I still do not understand what is a metasyntactic variable :( or what exactly is a placeholder

Answer 1

used in examples without context to demostrate logic or concept when variable names are not important.
for example, demonstrating if else in python
if foo:
bar
else:
biz
the code will work if say
foo = user_is_authorized #boolean
bar = display_page() #return page
biz = unauthorized() #return error

image opening a production code to fix a bug and insted using proper variable names the person who wrote it used foo, bar and biz.. not cool