Did you have any requirement to link email receiving in vtiger using mail manager with the project?
consider that you have the customer and you are the construction or B2C company where customer send a request for some development and you are using project module for all your requirement.
In this case if you wants to create a project than you have to copy paste the content from the email and create the project. also you have to create the contact and link to the project which is tedious task.
CRMTiger implement the feature so customer have an option to create a project from email.
1. There is an option under related Records called “Add project” which you will see when you open an email.
2. When you select a project it will open a project in Quick create view and it will auto create contact and bind to the project.
Let us know if you needs more information on this