Here, "attached" is an adjective. The sentence is, in effect, telling you that in addition to the email there is something 'extra' - a list. In (1), in contrast, you have a fully-fledged passive verb. A list has been attached is the passive version of I have attached a list.

Is it correct to say attached or attached?

“Attached is” would be correct if the subject is singular; if the subject is plural, then “attached are” is accurate. Depending on the subject of the sentence, the be-verb can become either singular “is” or plural “are” after “attached.” Therefore, both options are correct in their proper contexts.

Has attached meaning?

1 : connected or joined to something see the attached document a house with an attached garage. 2 : emotionally connected : having strong feelings of affection or connection These are happy and well-adjusted children who are very attached to their adoptive family.—