The developer tools are available within the production builds, tested with the
GitHub-released build v0.3.1-beta , as well as current master HEAD commit. This appears to
be caused by the devTools: true flag within the app options, visible in Figure 2.1.

const SECURITY_OPTIONS = {
...
webPreferences : {
/**
* Potential security risk options set explicitly even when default is favourable.
* Reference: https://electronjs.org/docs/tutorial/security
*/
devTools : true ,
...

in packages/fether-electron/src/main/app/options/config/index.js