`quarto use template` creates empty `_extensions` folder and fails to copy extensions

I have:

• searched the issue tracker for similar issues
• installed the latest version of Quarto CLI
• formatted my issue following the Bug Reports guide

Bug description

Summary

When running quarto use template organization/template, the extensions included in the template are not properly copied. An empty _extensions folder is created instead.

Steps to reproduce

1. Run: quarto use template organization/template-with-extensions
2. Observe that only template files are created
3. Check _extensions folder - it's empty

Actual behavior

• Template files are copied correctly
• An empty _extensions folder is created
• Extensions are not installed

Expected behavior

Extensions from the template should be installed along with the template files.

Your environment

• OS: MacOS Tahoe 26.1

Quarto check output

Quarto 99.9.9
[✓] Checking environment information...
Quarto cache location: /Users/matteolarcher/Library/Caches/quarto
[✓] Checking versions of quarto binary dependencies...
Pandoc version 3.8.3: OK
Dart Sass version 1.87.0: OK
Deno version 2.4.5: OK
Typst version 0.14.2: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
Version: 99.9.9
commit: def4986d546d2313a1f691631fc02a64ab985a92
Path: /Users/matteolarcher/GIT_repo/quarto-cli/package/dist/bin

[✓] Checking tools....................OK
TinyTeX: (not installed)
Chromium: (not installed)
VeraPDF: (not installed)

[✓] Checking LaTeX....................OK
Using: Installation From Path
Path: /Library/TeX/texbin
Version: 2023

[✓] Checking Chrome Headless....................OK
Using: Chrome found on system
Path: /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
Source: MacOS known location

[✓] Checking basic markdown render....OK

[✓] Checking R installation...........(None)

  Unable to locate an installed version of R.
  Install R from https://cloud.r-project.org/

[✓] Checking Python 3 installation....OK
Version: 3.12.2 (Conda)
Path: /opt/miniconda3/bin/python
Jupyter: 5.7.2
Kernels: python3, maple

[✓] Checking Jupyter engine render....OK

[✓] Checking Julia installation...