Firefox dev server manifest warnings

The
{
"content_security_policy": {
"extension_pages": "script-src 'self' http://localhost;object-src 'self';"
},
"key": "..."
}
{
"content_security_policy": {
"extension_pages": "script-src 'self' http://localhost;object-src 'self';"
},
"key": "..."
}
is causing
No description