.MOD UN/PACKER Web Edition

• LocalPacking happens entirely inside the browser's WebAssembly sandbox; no file is ever uploaded. Once the page assets have loaded you can go offline and still pack.
• IdenticalBINDAT / BINLAYOUT / RAW compilation and .MOD container assembly run the same code as the desktop tl2-mikuro-mod-packer — byte-for-byte identical output. File timestamps in the manifest are written at the millisecond precision the browser exposes (the desktop build has 100 ns precision); that tiny difference in one field affects neither game loading nor mod activation.
• BaseShips the full Runic base data (UNITS templates + LEVELSETS + collision geometry, 10269 files, ≈ 3 MB gzipped), so BASEFILE unit inheritance and MPP walk-grids bake completely in the browser — same result as the desktop build.
• MPPLevel walk-grids are generated in the browser (--mpp re): the walk-grid only needs the base collision geometry (9 MB, bundled), never the 160 MB of render meshes. New-map / edited-map mods work out of the box.
• ThreadsWith cross-origin isolation the page runs on wasm threads: DAT/LAYOUT compilation and container compression are genuinely parallel through rayon (the same parallel code as the desktop build), cutting large-mod packing to roughly 1/4 – 1/6 of the single-thread time. Output stays byte-for-byte identical to the single-thread and desktop builds; unsupported environments fall back to a single thread automatically.
• LimitsThe whole mod tree is read into memory to pack. Multi-hundred-MB mega components (huge level asset sets, very heavy MPP) can exceed the browser's 4 GB memory ceiling — use the desktop packer for those. Ordinary mods are unaffected.
• UnpackUnpacking is decompilation, not extraction: BINDAT / BINLAYOUT payloads are turned back into UTF-16LE text sources, byte-for-byte identical to what the desktop unpack produces (measured against the official GUTS unpacker across 13 mods / 90k+ files: 99.4% byte-identical, and the remainder is GUTS losing precision or failing to name a key).
• Name recoveryDAT key names survive in the container only as a one-way rghash; whatever cannot be reversed becomes UNK_<8 hex digits> — the data survives (the placeholder recompiles to the very same hash) but the readable name is gone, so never hand-edit those digits. Bundled now is a 465,361-entry tiered reverse table (real key positions / exe wide literals / curated dictionaries / numbered families / filenames / DAT values, merged most-trustworthy first, 1.31 MB compressed), plus the file's own basename and entire string table used as hints. Recovered names print green and spell out the placeholder they would have been (recovered: UNK_091C391F → SECOND_STAT); anything still unreversed prints red. Measured across 20 third-party mods (98,008 files): UNK_ down from 972 to 871, zero regressions, zero wrong names, and newly recovered keys like DISALLOWPVP / FORCEPVP / UNITREWARD exist only inside the exe, never in any shipped data file.
• TimestampsUnpacking does not restore file modification times (browsers cannot set them); the desktop build does. That only shows up in the manifest timestamp field after a repack, and does not affect game loading.

• ① PickHit Choose MOD folder and select the mod root (it needs MOD.DAT and MEDIA/). Chrome / Edge use the native folder picker; Firefox and others switch to directory upload automatically (still read locally only).
• ② ConfirmCheck the mod name and the output name (read automatically from MOD_FILE_NAME in MOD.DAT).
• ③ PackHit Pack into .MOD and download the result. Mods containing levels bake their MPP walk-grids along the way; use the desktop packer for mega components.
• ④ UnpackTo go the other way (read someone else's mod, or reopen an old build of your own) pick a .MOD in the Unpack section. Chrome / Edge let you choose an output folder and write straight into it; other browsers get a ZIP. What comes out is a source folder you can edit and feed straight back into Pack above.

"The same furnace, seen through a new window."