"The Dev. Team may also invite other people to attend in order to provide technical or domain advice."
Are these advisors also called "stakeholder"?
1) Short :Stakeholder of a product is everyone with an interest (or "stake") in what the product does.
2) Long ; assume that we are a development Team which implements a product (solution) a web-application for booking hotel rooms through internet. The end users , the normal people who use our web-application to book their rooms , are stakeholder for our the product , but also hotel managers for example who get specials account to register and update the information of their own hotels in the database, are also stakeholder for the product. These two examples were examples of external stakeholders.
a product has also internal stakeholders for example: IT Analyst , Developper, Product owner, release manage , operator , test team,... they are internal stakeholder of the product.
The stakeholders have completely different views and requirement. End user wish a user friendly GUI with Help textes but an operator who will be the responsible for running product in live system may be needs good document where the steps of patch installation are exactly described.
as you see the different groups and roles couldhave differentrequirements , It is a very important to identify all relevant stakeholder and consider their requirements on the product, to solve if there are conflicts among them.If we forget an important stakeholder , later could it cause huge extra cost to correct it or even we risk the product not be accepted at all. This analyisis normally happens during requirement analysis activities, In scrum the Product owner is responsible for that and involve all relevant stakeholders and consider their needs.
please be aware also that to identify all relevant stakeholder is not a easy task and needs domain know how , brainstörming, interviewing the experts. stakeholders are not always persons, they could be also impersonal such as ; standards , laws, , .... they have probably requirements for our product. for example in our hotel room booking application prabably international IT data security rules defines standards for handling of personal data of users,.... which must be fullfilled. Or an anti discriminiation law prescribes that for blind user our web-application must support offer read text feature .. etc.
Sometimes even special group of ilegal user "Hackers" could be considrate as stakeholders , in this odd case , the team must know what are typical ways of cyberattacks and these must be taken into consideration in design to prevent them. for example preventing a SQL-Injection attack on fileld of Graphical User Interface.