Solved Content/Core/mod.toml assets list references renamed files (FakeSubstances.xml / FakeCombustion.xml) that no longer exist.

[Maxi]

Game Version​

2026.7.5.4892

Operating System​

Windows 10

What Happened​

The stock Core content manifest references two asset files that no longer exist in the build.

• Content/Core/mod.toml still lists "FakeSubstances.xml" and "FakeCombustion.xml" in its assets array.
• Neither file is present in Content/Core/ anymore. Instead there are Substances.xml and Combustion.xml, which contain the actual substance and combustion-process definitions but nothing in the manifest points at them.
• When an XML import/patch pipeline walks the assets list and reaches FakeSubstances.xml, it throws a System.IO.FileNotFoundException.

@gravhoek This looks like a leftover from the Reactions / ThermoToolkit refactor (revision 4885: "Refactored combustion processes into a new concept: Reactions" + "Removed Nepetalactone, Actinidine, the LR91 Dev engine...").
The fake substance/combustion files were renamed to the real Substances.xml / Combustion.xml, but the assets list in Content/Core/mod.toml was not updated to match.

The exception surfaced for me at startup through a third-party XML-patching mod (its loader reads the Core manifest and imports every listed asset strictly), so I am aware this is not a "pure base game" repro. I am reporting it as a base-game issue because the defect is entirely in the shipped Core files and is verifiable without any mod by simply opening the manifest and listing the folder (steps below). It also breaks the XML patch/import path that the update explicitly intends to expose to modders ("This should be shipped with the game and available to modders" in the changelog).

What Was Expected​

The assets array in Content/Core/mod.toml should reference the files that actually ship - "Substances.xml" and "Combustion.xml" - so every listed asset resolves and the XML import/patch pipeline can load Core content without a FileNotFoundException.

Reproduction Steps​

1. Install / update to 2026.7.5.4892.
2. Open <install>/Content/Core/mod.toml and look at the assets = [ ... ] array (the entries are around lines 61 and 63).
3. Note that it lists "FakeSubstances.xml" and "FakeCombustion.xml".
4. List <install>/Content/Core/: neither file exists. Substances.xml and Combustion.xml are present instead, and are not referenced by the manifest.
5. Any consumer that imports each asset the manifest lists (the XML patch/import pipeline) throws FileNotFoundException on FakeSubstances.xml.

Reproduction Rate​

Always. The manifest/file mismatch is present in every install of this build.

Additional Info​

• Suggested fix: In Content/Core/mod.toml, change "FakeSubstances.xml" -> "Substances.xml" and "FakeCombustion.xml" -> "Combustion.xml". (Verified locally: pointing the two entries at the existing files resolves the missing-file error.)
• Likely introduced in: revision 4885 (the Reactions / ThermoToolkit refactor).

 

[gravhoek]

Thanks for the report! This should be fixed in the next public build.