Asmachta (Talmudical hermeneutics)

In Talmudical hermeneutics, asmachta is an allusion found in the Hebrew Bible for rabbinical prohibitions or any other Halakha. It's an exception in the talmudical hermeneutics, since it doesn't base the law on the cited verse, but uses the verse as a hint.
Sometimes it isn't clear whether the verse has been quoted as an "asmachta" or as a source, which can lead to controversy over the "de'oraita" or "derabanan" quality of the law. An example of such a case is the controversy over "berakhah she'eina tzricha" or "berakhah levatala", the prohibition to say a prayer outside its context. The Talmud says "Anyone who recites an unnecessary blessing violates the biblical prohibition: "Thou shalt not take the name of the Lord thy God in vain"". While Maimonides sees it as a source, the Tosafists see it as an "asmachta".
Meaning.
According to Maimonides, this is only a mnemonic the sages gave, as an aid to memory. The Kuzari makes a similar statement.
Yom Tov Asevilli (the Ritva) objects to Maimonides' explanation, and claims that God himself devised the various "asmachta" sources and embedded them in the Torah as allusions to be used by the sages.