Question: Does the regular expression `X•(Y*+Z)` accept the word `X`?

I would say it does, as `Y=ε` should fulfill the disjunction, but I'm not sure.

Answer: 
Yes, matching 0 times still counts as success.

Or, looking at it from the other direction, your regex generates

```
X
XY
XZ
XYY
XYYY
XYYYY
...

```
This answer is assuming that your regex could also be represented as `X.(Y*|Z)` in addition to your original of `X•(Y*|Z)` -- if that is not correct, please explain what `•` is supposed to do or represent.

`X•(Y*|Z)` necessitates that `X` be present before `Y*` or `Z` can match, but will not include `X` in the match's specific capture-group results, only the matching line. If you wanted to include `X`, you might re-write it as `(X)•(Y*|Z)` and extract `X` from capture group 1, and your disjunction match in capture group 2.