Longest Common Subsequence (LCS) - Why is the padded string Z_{x_m} a common subsequence of X and Y in the LCS problem?

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I am currently studying the Longest Common Subsequence problem. Here is how the problem is defined in the notes I am reading:

Let $X=x_1...x_m$ and $Y=y_1...y_n$ be strings. Let $Z=z_1...z_k$ denote their LCS.

The notes then state: If $Z$ does not end in the character $x_m$, then the padded string $Z_{x_m}$ is a common subsequence of X and Y longer than Z.

Is this essentially saying that, if:

$X=ADELOQ$

$Y=BEDUOEOQ$

$Z=DEO$

As Z does not end in the character $x_6=Q$, then the padded string DEOQ is the LCS.

Am I understanding what the statement is trying to say, or have I completely misunderstood?

Thank you!