package.js doesn't process theme files / iconsets on Windows.

[blendermf]

The path from import.meta.url used will fail with glob.sync on Windows because it returns a windows style path that's incompatible.

Changing the line
let projectPath = dirname(fileURLToPath(import.meta.url))
to
let projectPath = dirname(fileURLToPath(import.meta.url)).split(sep).join(posix.sep); fixes the issue.