You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allimages aicontinue="20190920070141|Shin2_Rias_i_Issei.png" />
  </query-continue>
  <query>
    <allimages>
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      <img name="Light_novel_(tom_DX_6)_okładka.jpg" timestamp="2021-03-19T10:08:12Z" user="Nightwing" url="https://hsdxd.usermd.net/w/images/e/e9/Light_novel_%28tom_DX_6%29_ok%C5%82adka.jpg" descriptionurl="https://hsdxd.usermd.net/wiki/Plik:Light_novel_(tom_DX_6)_ok%C5%82adka.jpg" ns="6" title="Plik:Light novel (tom DX 6) okładka.jpg" />
      <img name="Light_novel_(tom_DX_5)_okładka.jpg" timestamp="2021-03-19T10:06:12Z" user="Nightwing" url="https://hsdxd.usermd.net/w/images/e/e2/Light_novel_%28tom_DX_5%29_ok%C5%82adka.jpg" descriptionurl="https://hsdxd.usermd.net/wiki/Plik:Light_novel_(tom_DX_5)_ok%C5%82adka.jpg" ns="6" title="Plik:Light novel (tom DX 5) okładka.jpg" />
      <img name="Light_novel_Shin_(tom_4)_okładka.jpg" timestamp="2020-02-20T20:05:19Z" user="Nightwing" url="https://hsdxd.usermd.net/w/images/3/37/Light_novel_Shin_%28tom_4%29_ok%C5%82adka.jpg" descriptionurl="https://hsdxd.usermd.net/wiki/Plik:Light_novel_Shin_(tom_4)_ok%C5%82adka.jpg" ns="6" title="Plik:Light novel Shin (tom 4) okładka.jpg" />
      <img name="Lint_Sellzen(light_novel_art)_wygląd_postaci.png" timestamp="2019-09-29T21:06:15Z" user="Nightwing" url="https://hsdxd.usermd.net/w/images/e/e4/Lint_Sellzen%28light_novel_art%29_wygl%C4%85d_postaci.png" descriptionurl="https://hsdxd.usermd.net/wiki/Plik:Lint_Sellzen(light_novel_art)_wygl%C4%85d_postaci.png" ns="6" title="Plik:Lint Sellzen(light novel art) wygląd postaci.png" />
      <img name="Elmenhilde_Galnstein_(light_novel_art)_wygląd_postaci_2.jpg" timestamp="2019-09-29T20:58:59Z" user="Nightwing" url="https://hsdxd.usermd.net/w/images/a/a6/Elmenhilde_Galnstein_%28light_novel_art%29_wygl%C4%85d_postaci_2.jpg" descriptionurl="https://hsdxd.usermd.net/wiki/Plik:Elmenhilde_Galnstein_(light_novel_art)_wygl%C4%85d_postaci_2.jpg" ns="6" title="Plik:Elmenhilde Galnstein (light novel art) wygląd postaci 2.jpg" />
      <img name="Lavinia_Reni_(light_novel)_1.jpg" timestamp="2019-09-29T18:29:40Z" user="Nightwing" url="https://hsdxd.usermd.net/w/images/f/fb/Lavinia_Reni_%28light_novel%29_1.jpg" descriptionurl="https://hsdxd.usermd.net/wiki/Plik:Lavinia_Reni_(light_novel)_1.jpg" ns="6" title="Plik:Lavinia Reni (light novel) 1.jpg" />
      <img name="Shin2_Vasco_Strada.png" timestamp="2019-09-20T07:05:07Z" user="Songoku4xd" url="https://hsdxd.usermd.net/w/images/6/6b/Shin2_Vasco_Strada.png" descriptionurl="https://hsdxd.usermd.net/wiki/Plik:Shin2_Vasco_Strada.png" ns="6" title="Plik:Shin2 Vasco Strada.png" />
      <img name="Shin2_Asia_Argento_i_Crom_Cruach.png" timestamp="2019-09-20T07:02:01Z" user="Songoku4xd" url="https://hsdxd.usermd.net/w/images/4/46/Shin2_Asia_Argento_i_Crom_Cruach.png" descriptionurl="https://hsdxd.usermd.net/wiki/Plik:Shin2_Asia_Argento_i_Crom_Cruach.png" ns="6" title="Plik:Shin2 Asia Argento i Crom Cruach.png" />
      <img name="Shin2_Lint_Sellzen_and_Ouryuu_Nakiri.png" timestamp="2019-09-20T07:01:50Z" user="Songoku4xd" url="https://hsdxd.usermd.net/w/images/d/d0/Shin2_Lint_Sellzen_and_Ouryuu_Nakiri.png" descriptionurl="https://hsdxd.usermd.net/wiki/Plik:Shin2_Lint_Sellzen_and_Ouryuu_Nakiri.png" ns="6" title="Plik:Shin2 Lint Sellzen and Ouryuu Nakiri.png" />
    </allimages>
  </query>
</api>