begin{tabulary}{linewidth}{|L|L|L|}
hline
textsf{relax
Nummer
} & textsf{relax
Name
} & textsf{relax
Bemerkungen
}\
hline
0
 &
Allgemeines
 &
Enthält Meta-Informationen zum Dossier
\
[...]
hlineend{tabulary}

RequirePackage{tabu}

definecolor{tablehead}{rgb}{0.7294117647058823, 0.6823529411764706, 0.6235294117647059}

renewenvironment{tabulary}[2]{bgroupbegin{tabu} to textwidth{#2}
    rowcolor{tablehead}
}%
{end{tabu}egroup}

! Missing # inserted in alignment preamble.
<to be read again>
                   &
l.294 hlineend{tabulary}

? x

documentclass{article}
usepackage[T1]{fontenc}
usepackage[utf8]{inputenc}
usepackage[ngerman]{babel}

usepackage{tabu,tabulary}
usepackage[table]{xcolor}

definecolor{tablehead}{rgb}{0.7294117647058823, 0.6823529411764706, 0.6235294117647059}

% redefine the L column type
newcolumntype{L}{X[l]<{strut}}

renewenvironment{tabulary}[3]
 {noindenttabu to textwidth{#2}hlinerowcolor{tablehead}}
 {endtabu}


begin{document}

begin{tabulary}{linewidth}{|L|L|L|}
hline
textsf{Nummer} & textsf{Name} & textsf{Bemerkungen}\
%hline
0
 &
Allgemeines
 &
Enthält Meta-Informationen zum Dossier
\
hline
end{tabulary}

end{document}

_templates/latex.tex_t
_templates/longtable.tex_t
_templates/tabular.tex_t
_templates/tabulary.tex_t