LocalLeet от Cheezer

A browser extension for Chrome and Firefox that runs LeetCode testcases locally, in your browser, using
WebAssembly builds of language toolchains. Python (via Pyodide) and C++ (via Clang/LLD from
YoWASP) are supported, and the code is laid out so other languages can be added.

• Adds a Local button next to LeetCode's Run button, and a shortcut: Ctrl/⌘ + Shift + '.
• Shows results in a LocalLeet tab next to LeetCode's own Test Result tab. A floating panel is used only if
  that tab can't be found.
• Runs your code from the editor against the testcases in LeetCode's Testcase panel, including ones you add or edit.
• Compares each output against the expected output from the problem's examples when the input matches an
  example. For problems that say "in any order", it also accepts the answer in any order.
• Remembers the expected outputs LeetCode shows when you use its own Run or Submit, so running those
  inputs locally later gets a verdict. Run gives the expected output of every testcase you ran, custom ones
  included. A failed Submit gives the hidden testcase it failed on. Those cases are listed under
  Testcases from failed submissions in the LocalLeet tab, with a button that adds them to the Testcase panel.
  The outputs are kept in the extension's local storage (at most 500 per problem) and can be cleared on the
  options page.
• Shows output, stdout and a filtered traceback per case, with LeetCode-style verdicts (Accepted, Wrong Answer,
  Runtime Error, Time Limit Exceeded, Compile Error).
• Handles plain functions, in-place (void) problems, ListNode/TreeNode inputs and outputs, design problems
  (["LRUCache","put",...]), and the common custom-judge problems (linked list cycle, intersection, LCA, clone
  graph).
• Mirrors LeetCode's Python environment: the usual standard-library star imports, typing, and sortedcontainers.
• Mirrors LeetCode's C++ environment: C++23 at -O2, the whole standard library (including <bits/stdc++.h>),
  using namespace std, and ListNode/TreeNode. Runtime errors come out the way LeetCode's sanitizers report
  them, e.g. Line 4: Char 18: runtime error: signed integer overflow: ... or member access within null pointer.