the character string specified by the Meta tag in the HTML document

(from github.com/o-matsuo)
i have a question.
Is it impossible to specify the character string specified by the Meta tag in the HTML document as a search word?

(from github.com/marevol)
See https://github.com/codelibs/fess/issues/1634#issuecomment-386439257

(from github.com/o-matsuo)
thank you!