文件xetex.ini生成時使用xetex.fmt。
%% xetex.ini
% General Unicode set up
\input load-unicode-data.tex %
% Classes that have always been defined by the XeTeX format
\input load-unicode-xetex-classes.tex %
此 .ini 檔案載入load-unicode-data.tex和load-unicode-xetex-classes.tex。但在生成時xelatex.fmt，使用的文件xelatex.ini似乎load-unicode-data.tex僅加載第一個文件（通過latex.ltx）。
我搜尋了 Latex2e 的儲存庫，但找不到第二個文件的任何內容load-unicode-xetex-classes.tex。為什麼這個檔案只能由xetex.ini輸入？
答案1
TeX Live 和 MiKTeX 使用的檔案.ini最初是作為處理 DVI 的簡單方法相對PDF 輸出：latex.ini和pdflatex.ini.然而，它們隨著時間的推移而增長，尤其是那些純 TeX 格式的格式。原因是，對於普通來說，Knuth 僅支援文件中的原始 TeX (TeX90)，而該文件（按照慣例）不能被其他人更改。從而支援 XeTeX、LuaTeX 的關鍵功能，ETC。，向文件添加程式碼.ini是必要的。
在一段時間內，也沒有進行任何更改latex.ltx，因此各種東西都收集在xelatex.ini,ETC。不久前，團隊決定積極支持 XeTeX 和 LuaTeX，並將大量程式碼從檔案移.ini回latex.ltx.
如果你查看ltfinal.dtx（最後一部分的來源latex.ltx），你會發現load-unicode-xetex-classes 是閱讀：目前的來源部分說
% \changes{v2.0a}{2015/01/03}{Unicode data loading added}
% \changes{v2.0c}{2015/01/24}{Skip T1-code entirely with Unicode engines}
% \changes{v2.0d}{2015/03/26}{Use renamed
% \texttt{unicode-letters.def}}
% \changes{v2.0i}{2015/12/10}{Use new common Unicode data loaders}
% \changes{v2.0j}{2016/01/04}{Do not set up inter character classes for
% XeTeX}
% \changes{v2.0l}{2016/01/05}{Correct \textsf{latexrelease} guards}
% \changes{v2.0l}{2016/01/05}{Ensure old definitions for inter-character
% class toks are available using \textsf{latexrelease}}
% \changes{v2.0m}{2016/01/05}{Undefine XeTeX classes when using patching
% an older kernel}
% \changes{v2.0l}{2016/01/05}{Missing brace}
% \changes{v2.0p}{2016/01/05}{Only apply XeTeX change if XeTeX is in use}
% For $7$- and $8$-bit engines the assumption of T1 encodings is the
% basis for the hyphenation patterns. That's not the case for the Unicode
% engines, where the assumption is engine-native working. The common
% loader system provides access to data from the Unicode Consortium
% covering not only |\lccode| but also other related data. The
% |\lccode| part of that at least needs to be loaded before hyphenation is
% tackled: Xe\TeX{} follows the standard \TeX{} route of building patterns
% into the format. Lua\TeX{} doesn't require this data be loaded \emph{here}
% but it does need to be loaded somewhere. Rather than test for the Unicode
% engines by name, the approach here is to look for the extended math mode
% handling both provide: any other engine developed in this area will
% presumably also provide |\Umathcode|.
% \begin{macrocode}
\ifnum 0%
\ifx\Umathcode\@undefined\else 1\fi
\ifx\XeTeXmathcode\@undefined\else 1\fi
>\z@
\message{ Unicode character data,}
\input{load-unicode-data}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2016/02/01}%
%<latexrelease> {\XeTeXintercharclasses}{XeTeX character classes}%
%<latexrelease> \ifx\XeTeXinterchartoks\undefined
%<latexrelease> \else
%<latexrelease> \begingroup
%<latexrelease> \chardef\XeTeXcharclassID = 0 %
%<latexrelease> \chardef\XeTeXcharclassOP = 0 %
%<latexrelease> \chardef\XeTeXcharclassCL = 0 %
%<latexrelease> \chardef\XeTeXcharclassEX = 0 %
%<latexrelease> \chardef\XeTeXcharclassIS = 0 %
%<latexrelease> \chardef\XeTeXcharclassNS = 0 %
%<latexrelease> \chardef\XeTeXcharclassCM = 0 %
%<latexrelease> \input{load-unicode-xetex-classes}
%<latexrelease> \endgroup
%<latexrelease> \global\let\xtxHanGlue\undefined
%<latexrelease> \global\let\xtxHanSpace\undefined
%<latexrelease> \global\XeTeXinterchartoks 0 1 = {}
%<latexrelease> \global\XeTeXinterchartoks 0 2 = {}
%<latexrelease> \global\XeTeXinterchartoks 0 3 = {}
%<latexrelease> \global\XeTeXinterchartoks 1 0 = {}
%<latexrelease> \global\XeTeXinterchartoks 2 0 = {}
%<latexrelease> \global\XeTeXinterchartoks 3 0 = {}
%<latexrelease> \global\XeTeXinterchartoks 1 1 = {}
%<latexrelease> \global\XeTeXinterchartoks 1 2 = {}
%<latexrelease> \global\XeTeXinterchartoks 1 3 = {}
%<latexrelease> \global\XeTeXinterchartoks 2 1 = {}
%<latexrelease> \global\XeTeXinterchartoks 2 2 = {}
%<latexrelease> \global\XeTeXinterchartoks 2 3 = {}
%<latexrelease> \global\XeTeXinterchartoks 3 1 = {}
%<latexrelease> \global\XeTeXinterchartoks 3 2 = {}
%<latexrelease> \global\XeTeXinterchartoks 3 3 = {}
%<latexrelease> \fi
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000/00/00}%
%<latexrelease> {\XeTeXintercharclasses}{XeTeX character classes}%
%<latexrelease> \ifx\XeTeXinterchartoks\undefined
%<latexrelease> \else
%<latexrelease> \input{load-unicode-xetex-classes}
%<latexrelease> \gdef\xtxHanGlue{\hskip0pt plus 0.1em\relax}
%<latexrelease> \gdef\xtxHanSpace{\hskip0.2em plus 0.2em minus 0.1em\relax}
%<latexrelease> \global\XeTeXinterchartoks 0 1 = {\xtxHanSpace}
%<latexrelease> \global\XeTeXinterchartoks 0 2 = {\xtxHanSpace}
%<latexrelease> \global\XeTeXinterchartoks 0 3 = {\nobreak\xtxHanSpace}
%<latexrelease> \global\XeTeXinterchartoks 1 0 = {\xtxHanSpace}
%<latexrelease> \global\XeTeXinterchartoks 2 0 = {\nobreak\xtxHanSpace}
%<latexrelease> \global\XeTeXinterchartoks 3 0 = {\xtxHanSpace}
%<latexrelease> \global\XeTeXinterchartoks 1 1 = {\xtxHanGlue}
%<latexrelease> \global\XeTeXinterchartoks 1 2 = {\xtxHanGlue}
%<latexrelease> \global\XeTeXinterchartoks 1 3 = {\nobreak\xtxHanGlue}
%<latexrelease> \global\XeTeXinterchartoks 2 1 = {\nobreak\xtxHanGlue}
%<latexrelease> \global\XeTeXinterchartoks 2 2 = {\nobreak\xtxHanGlue}
%<latexrelease> \global\XeTeXinterchartoks 2 3 = {\xtxHanGlue}
%<latexrelease> \global\XeTeXinterchartoks 3 1 = {\xtxHanGlue}
%<latexrelease> \global\XeTeXinterchartoks 3 2 = {\xtxHanGlue}
%<latexrelease> \global\XeTeXinterchartoks 3 3 = {\nobreak\xtxHanGlue}
%<latexrelease> \fi
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
% \changes{v2.0d}{2015/02/03}{Set \cs{lccode} for \texttt{-} with Unicode
% engines}
% There is one over-ride that makes sense here (see below for the same for
% $8$-bit engines): setting the lccode for |-| to itself.
% \begin{macrocode}
\lccode`\- =`\- % default hyphen char
% \end{macrocode}
您將看到有兩個版本的 XeTeX 類別載入：反映.ini檔案中的更改，ETC。
對於純 TeX，僅有的將 Unicode 資料載入到該格式的方法是在.ini文件中。因此，載入程式與其他載入程式（例如 Unicode 基本資料和 Unicode 數學模式資訊）一起存在。