documentclass[12pt]{article}
usepackage[utf8]{inputenc}
usepackage[T1]{fontenc}

usepackage{xsim}
usepackage{geometry}
geometry{a4paper}
usepackage{layout}


begin{document}
    blank[width=10linewidth]{}%
end{document}

documentclass[12pt]{article}
usepackage[utf8]{inputenc}
usepackage[T1]{fontenc}
usepackage[pass,showframe]{geometry}
usepackage{xsim}

textwidth=10.09pt
begin{document}
    blank[width=10linewidth]{}%
end{document}

Overfull hbox (0.91pt too wide) in paragraph at lines 29--29
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