placeholder and replacement string. The array needs to be
terminated by an entry with placeholder set to NULL.
+`strbuf_addbuf_percentquote`::
+
+ Append the contents of one strbuf to another, quoting any
+ percent signs ("%") into double-percents ("%%") in the
+ destination. This is useful for literal data to be fed to either
+ strbuf_expand or to the *printf family of functions.
+
`strbuf_addf`::
Add a formatted string to the buffer.