Difficulty with 3 search prefixes name:~* name:* and text:*

From the example in the Help: Name contains tech → name:~tech.

And a thorough explanation of the two…
For an item named DEVONtechnologies:

• name:~tech matches as the substring is contained anywhere in the name.

• name:tech does not match as there is no word tech in the name.

• name:tech* does not match as there is no word beginning with tech.

• name:*tech does not match as the substring is found but not at the end of the word.

• name:*tech* matches as tech is matched with text before and after it. However, unless you have a specific purpose, using the contains operator is more succinct.

PS: Bear in mind, the wildcard is not RegEx.