Describe the bug

Consider this source using raw horizontal tabulation character ascii 09 (TAB char).

..code-block::   "23456781234567812345678123456781234567812345678"   mystring = r"aababcabcdabcdebar"

(take into account the github markdown uses tab stops every 4 spaces, this was done in an editor using 8 spaces per tab).

Then the HTML will use spaces, not tabs in<pre>...</pre>.

<div><div><pre><span></span><span>&quot;23456781234567812345678123456781234567812345678&quot;</span><span>mystring</span> <span>=</span> <span>r</span><span>&quot;a       ab      abc     abcd    abcde   bar&quot;</span></pre></div>

This contains no tabulation characters. So copying-pasting does not allow to recover the original source code.

How to Reproduce

Use above inindex.rst and excutemake html.

Environment Information

Platform:              darwin; (macOS-15.7.2-arm64-arm-64bit-Mach-O)Python version:        3.13.3 (v3.13.3:6280bb54784, Apr  8 2025, 10:47:54) [Clang 15.0.0 (clang-1500.3.9.4)])Python implementation: CPythonSphinx version:        8.3.0+/5d0ad1686Docutils version:      0.22.4b1.devJinja2 version:        3.1.6Pygments version:      2.19.1

Sphinx extensions

Additional context

On the other hand,literalinclude preserves horizontal tab characters.

Originally fromthis comment.

I presume this is a well-known fact, which simply illustrates the utility of attachment of the true source code.