data for the production of the XMM-LSS survey catalogues, which can be considered the precursors of the present catalogue on a smaller area (see Table \[TabCat\]). For this reason we prefix all sources in the current catalogue with `3XLSS`.

With respect to the newer pipeline reference paper, , all catalogues produced to date, including the present one, use pipeline versions collectively grouped as the basic version called `XAminP06` in paper XXIV; in other words, detections are done on each pointing separately.

Version 3.3.2 of the pipeline differs from earlier versions in relatively minor details, including an optimisation of the code for the detection of point sources, especially bright ones, with a fix for some numeric problems. They will be retained in the newer `XAminF18` pipeline presented in .

  ----------- ----------------------------------------------------- ------- ----------- --------- ------
    Catalogue <span style="font-variant:small-caps;">Xamin</span>                  Area     N. of  Ref.
      acronym version                                                         (deg$^2$)   sources 
       `XLSS` 3.1                                                                   5.5      3385   1
      `2XLSS` 3.2                                                                  11.1      5572   2
     `2XLSSd` 3.2                                                                  11.1      6721   2
      `3XLSS` 3.3.2                                                 XXL-N            25     14168   3
                                                                    XXL-S            25     11888 
  ----------- ----------------------------------------------------- ------- ----------- --------- ------

  : XMM-LSS and XXL X-ray catalogues[]{data-label="TabCat"}

As described in section 2.1 of , the basic pipeline starts from event lists filtered for soft proton flares, 