Jupyter labへのvariable inspectorインストールができない（Field 'browser' doesn't contain a valid alias）

Question

前提・実現したいこと

Jupyter labにvariavle inspectorをインストールしたい

発生している問題・エラーメッセージ

conda install -c conda-forge nodejs
jupyter labextension install @lckr/jupyterlab_variableinspector
jupyter lab build
を行うと、以下のようなエラーが出てきました。

An error occured.
RuntimeError: JupyterLab failed to build
See the log file for details:  C:\Users\xxxxx\AppData\Local\Temp\jupyterlab-debug-irl0hcwp.log

ログファイルは以下です。

[LabBuildApp] Building in C:\Users\xxxxx\anaconda3\share\jupyter\lab
[LabBuildApp] Node v14.8.0

（中略）

ERROR in resolving fallback for shared module @lckr/jupyterlab_variableinspector
Module not found: Error: Can't resolve '@lckr/jupyterlab_variableinspector' in 'C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\build'
resolve '@lckr/jupyterlab_variableinspector' in 'C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\build'
  Parsed request is a module
  using description file: C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\build\package.json (relative path: .)
    Field 'browser' doesn't contain a valid alias configuration
    resolve as module
      C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\build\node_modules doesn't exist or is not a directory
      looking for modules in C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules
        single file module
          using description file: C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\package.json (relative path: ./node_modules/@lckr/jupyterlab_variableinspector)
            no extension
              Field 'browser' doesn't contain a valid alias configuration
              C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector is not a file
            .js
（中略）

C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector\lib\index.js doesn't exist
                        .js
                          Field 'browser' doesn't contain a valid alias configuration
                          C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector\lib\index.js.js doesn't exist
                        .json
                          Field 'browser' doesn't contain a valid alias configuration
                          C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector\lib\index.js.json doesn't exist
                        .wasm
                          Field 'browser' doesn't contain a valid alias configuration
                          C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector\lib\index.js.wasm doesn't exist
                        as directory
                          C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector\lib\index.js doesn't exist
                    using path: C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector\index
                      using description file: C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector\package.json (relative path: ./index)
                        no extension
                          Field 'browser' doesn't contain a valid alias configuration
                          C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector\index doesn't exist
                        .js
                          Field 'browser' doesn't contain a valid alias configuration
                          C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector\index.js doesn't exist
                        .json
                          Field 'browser' doesn't contain a valid alias configuration
                          C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector\index.json doesn't exist
                        .wasm
                          Field 'browser' doesn't contain a valid alias configuration
                          C:\Users\xxxxx\anaconda3\share\jupyter\lab\staging\node_modules\@lckr\jupyterlab_variableinspector\index.wasm doesn't exist
      C:\Users\xxxxx\anaconda3\share\jupyter\lab\node_modules doesn't exist or is not a directory
      C:\Users\xxxxx\anaconda3\share\jupyter\node_modules doesn't exist or is not a directory
      C:\Users\xxxxx\anaconda3\share\node_modules doesn't exist or is not a directory
      looking for modules in C:\Users\xxxxx\anaconda3\node_modules
        single file module
          No description file found in C:\Users\xxxxx\anaconda3\node_modules\@lckr or above
          no extension
            Field 'browser' doesn't contain a valid alias configuration
            C:\Users\xxxxx\anaconda3\node_modules\@lckr\jupyterlab_variableinspector doesn't exist
          .js
            Field 'browser' doesn't contain a valid alias configuration
            C:\Users\xxxxx\anaconda3\node_modules\@lckr\jupyterlab_variableinspector.js doesn't exist
          .json
            Field 'browser' doesn't contain a valid alias configuration
            C:\Users\xxxxx\anaconda3\node_modules\@lckr\jupyterlab_variableinspector.json doesn't exist
          .wasm
            Field 'browser' doesn't contain a valid alias configuration
            C:\Users\xxxxx\anaconda3\node_modules\@lckr\jupyterlab_variableinspector.wasm doesn't exist
        C:\Users\xxxxx\anaconda3\node_modules\@lckr\jupyterlab_variableinspector doesn't exist
      C:\Users\xxxxx\node_modules doesn't exist or is not a directory
      C:\Users\node_modules doesn't exist or is not a directory
      C:\node_modules doesn't exist or is not a directory

webpack 5.37.0 compiled with 1 error and 1 warning in 57352 ms

asset index.css 16.1 KiB [compared for emit] (name: index)
asset index.js 0 bytes [compared for emit] [minimized] (name: index)
Entrypoint index 16.1 KiB = index.css 16.1 KiB index.js 0 bytes
./node_modules/@jupyterlab/theme-dark-extension/style/index.css 50 bytes [built] [code generated]
css ./node_modules/css-loader/dist/cjs.js!./node_modules/@jupyterlab/theme-dark-extension/style/variables.css 15.3 KiB [code generated]
css ./node_modules/css-loader/dist/cjs.js!./node_modules/@jupyterlab/theme-dark-extension/style/base.css 472 bytes [code generated]
css ./node_modules/css-loader/dist/cjs.js!./node_modules/@jupyterlab/theme-dark-extension/style/index.css 342 bytes [code generated]
webpack 5.37.0 compiled successfully in 4340 ms

asset index.css 15 KiB [compared for emit] (name: index)
asset index.js 0 bytes [compared for emit] [minimized] (name: index)
Entrypoint index 15 KiB = index.css 15 KiB index.js 0 bytes
./node_modules/@jupyterlab/theme-light-extension/style/index.css 50 bytes [built] [code generated]
css ./node_modules/css-loader/dist/cjs.js!./node_modules/@jupyterlab/theme-light-extension/style/variables.css 14.2 KiB [code generated]
css ./node_modules/css-loader/dist/cjs.js!./node_modules/@jupyterlab/theme-light-extension/style/base.css 472 bytes [code generated]
css ./node_modules/css-loader/dist/cjs.js!./node_modules/@jupyterlab/theme-light-extension/style/index.css 342 bytes [code generated]
webpack 5.37.0 compiled successfully in 4407 ms
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[LabBuildApp] JupyterLab failed to build
[LabBuildApp] Traceback (most recent call last):

[LabBuildApp]   File "C:\Users\xxxxx\anaconda3\lib\site-packages\jupyterlab\debuglog.py", line 47, in debug_logging
    yield

[LabBuildApp]   File "C:\Users\xxxxx\anaconda3\lib\site-packages\jupyterlab\labapp.py", line 166, in start
    raise e

[LabBuildApp]   File "C:\Users\xxxxx\anaconda3\lib\site-packages\jupyterlab\labapp.py", line 162, in start
    build(name=self.name, version=self.version,

[LabBuildApp]   File "C:\Users\xxxxx\anaconda3\lib\site-packages\jupyterlab\commands.py", line 469, in build
    return handler.build(name=name, version=version, static_url=static_url,

[LabBuildApp]   File "C:\Users\xxxxx\anaconda3\lib\site-packages\jupyterlab\commands.py", line 678, in build
    raise RuntimeError(msg)

[LabBuildApp] RuntimeError: JupyterLab failed to build

[LabBuildApp] Exiting application: JupyterLab

試したこと

jupyterlabをアンインストール、再インストールしたり、variable inspectorのアンインストール／再インストールをしても、症状は変わりませんでした。何か原因を思いつかれる方、お教えいただけますと幸いです。

補足情報（FW/ツールのバージョンなど）

jupyterlab 3.0.16
nodejs 14.8.0