ERROR: Cannot install torch==2.6.0+cu126, torch==2.7.0+cu126, torch==2.7.1+cu126 and torch==2.8.0+cu126 because these package versions have conflicting dependencies.

Steps to recreate (Debian Linux 12 Bookworm):
```
python3 -m venv venv
. venv/bin/activate
pip install torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cu126
```

Output (fix is below):
```
Looking in indexes: https://download.pytorch.org/whl/cu126
Collecting torch
Obtaining dependency information for torch from https://download.pytorch.org/whl/cu126/torch-2.8.0%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata
Downloading https://download.pytorch.org/whl/cu126/torch-2.8.0%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata (30 kB)
Collecting torchvision
Obtaining dependency information for torchvision from https://download.pytorch.org/whl/cu126/torchvision-0.23.0%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata
Downloading https://download.pytorch.org/whl/cu126/torchvision-0.23.0%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata (6.1 kB)
Collecting torchaudio
Obtaining dependency information for torchaudio from https://download.pytorch.org/whl/cu126/torchaudio-2.8.0%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata
Downloading https://download.pytorch.org/whl/cu126/torchaudio-2.8.0%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata (7.2 kB)
Collecting filelock
Obtaining dependency information for filelock from https://download.pytorch.org/whl/filelock-3.13.1-py3-none-any.whl.metadata
Using cached https://download.pytorch.org/whl/filelock-3.13.1-py3-none-any.whl.metadata (2.8 kB)
Collecting typing-extensions>=4.10.0
Obtaining dependency information for typing-extensions>=4.10.0 from https://download.pytorch.org/whl/typing_extensions-4.12.2-py3-none-any.whl.metadata
Using cached https://download.pytorch.org/whl/typing_extensions-4.12.2-py3-none-any.whl.metadata (3.0 kB)
Discarding https://download.pytorch.org/whl/typing_extensions-4.12.2-py3-none-any.whl#sha256=04e5ca0351e0f3f85c6853954072df659d0d13fac324d0072316b67d7794700d (from https://download.pytorch.org/whl/cu126/typing-extensions/): Requested typing-extensions>=4.10.0 from https://download.pytorch.org/whl/typing_extensions-4.12.2-py3-none-any.whl#sha256=04e5ca0351e0f3f85c6853954072df659d0d13fac324d0072316b67d7794700d (from torch) has inconsistent Name: expected 'typing-extensions', but metadata has 'typing_extensions'
Collecting torch
Obtaining dependency information for torch from https://download.pytorch.org/whl/cu126/torch-2.7.1%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata
Downloading https://download.pytorch.org/whl/cu126/torch-2.7.1%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata (29 kB)
Obtaining dependency information for torch from https://download.pytorch.org/whl/cu126/torch-2.7.0%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata
Downloading https://download.pytorch.org/whl/cu126/torch-2.7.0%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata (29 kB)
Obtaining dependency information for torch from https://download.pytorch.org/whl/cu126/torch-2.6.0%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata
Downloading https://download.pytorch.org/whl/cu126/torch-2.6.0%2Bcu126-cp311-cp311-manylinux_2_28_x86_64.whl.metadata (28 kB)
ERROR: Cannot install torch==2.6.0+cu126, torch==2.7.0+cu126, torch==2.7.1+cu126 and torch==2.8.0+cu126 because these package versions have conflicting dependencies.

The conflict is caused by:
torch 2.8.0+cu126 depends on typing-extensions>=4.10.0
torch 2.7.1+cu126 depends on typing-extensions>=4.10.0
torch 2.7.0+cu126 depends on typing-extensions>=4.10.0
torch 2.6.0+cu126 depends on typing-extensions>=4.10.0

To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict

ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts
```

Fix:
```
pip install typing-extensions
pip install torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cu126
```

Start by reproducing the installation in the issue on Debian 12 with a fresh Python virtual environment, then try the two-step fix shown. Inspect the repository's installation guidance for where these commands belong. Done means the CUDA 12.6 torch, torchvision, and torchaudio packages install without the dependency-resolution error.

Written by the indexing model from the issue text.