Reference (microsoft/vscode#31168)
find /usr/share/ -name "product.json"
# cd into vscodum directory
cd /usr/share/vscodium-bin/resources/app
# macOS
# /Applications/VSCodium.app/Contents/Resources/app/product.json
# Windows 10
# C:\Program Files\VSCodium\resources\app\product.json
nano product.json
# search for "extensionsGallery" and replace it with
"extensionsGallery": {
"serviceUrl": "https://marketplace.visualstudio.com/_apis/public/gallery",
"cacheUrl": "https://vscode.blob.core.windows.net/gallery/index",
"itemUrl": "https://marketplace.visualstudio.com/items"
}