When is that User Exit triggered ?

We enhanced 2LIS_11_VASCL via a user exit as below:

But when is that user exit triggered ? <b>In which extraction phase</b> ?

<i>

(asking that question due to delta issues)</i>

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CASE i_datasource.

WHEN '2LIS_11_VASCL'.

DATA: lt_data TYPE TABLE OF mc11va0scl.

DATA: ls_data LIKE mc11va0scl.

lt_data[] = c_t_data[].

LOOP AT lt_data INTO ls_data.

SELECT SINGLE aufnr INTO ls_data-aufnr

FROM vbap WHERE vbeln EQ ls_data-vbeln

AND posnr EQ ls_data-posnr.

MODIFY lt_data FROM ls_data.

ENDLOOP.

IF sy-subrc EQ 0.

c_t_data[] = lt_data[].

ENDIF.

ENDCASE.

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