This summary is not the rule. The rule text controls.
Here's what this rule means in plain terms.
If someone is charged with forgery, but the forged document was destroyed or hidden by the person accused of the crime, the prosecution doesn't need to describe that document perfectly in the charging papers. The law recognizes that you can't accurately describe a document that the defendant made disappear.
For this rule to apply, two things must happen. First, the charging document must state that the defendant destroyed or hid the forged item. Second, this fact must be proven at trial. If both of these things are shown, then small mistakes or gaps in describing the actual document don't matter and won't get the case thrown out.
This rule exists to stop people from benefiting from destroying evidence. Without it, someone could destroy a forged check or document, then argue the charges should be dismissed because the document wasn't described with perfect accuracy. This rule closes that loophole. It means a defendant cannot escape a forgery charge simply by getting rid of the evidence and then complaining that the paperwork about the case wasn't detailed enough.