A Named Townie is a role that has no real abilities, but differs from a normal Vanilla Townie in the sense it has a different name from an actual Vanilla Townie. This in itself can be powerful.
A Named Townie has no powers that differ from those of a Vanilla Townie; the only difference is in the role name itself. Thus, the player will be given a different name in their Role PM, a Rolecop will see the changed name, and so on.
Probably the most commonly used name for Vanilla Townies in the abstract is "Chocolate Townie", although they're more commonly named to something that makes sense in the theme.
In practice, any character that has a name is technically a Named Townie, although not by function. This was a trope subverted in Mini 1975: A Village in the Woods where some players had names, others names and roles, and some players simply roles.
Use & Balance
In Open setups Named Townies are remarkably powerful - the Named Townie can claim their role, and unless scum are brave (or foolhardy) enough to counterclaim them the claim is evidently true - and thus often, so is their alignment.
Useless roles such as a Miller with no Cop are considered to be variants on the Named Townie. These useless roles are weaker than a townie with just a name as they may be under the impression their corresponding role is in the game, and this could in theory offer scum opportunity to freely claim this role.
There is little that can differentiate a Named Townie from a Vanilla Townie, however by not being a VT it can itself be considered a kind of power. If a massclaim can be beneficial to the town, consider insisting going after a player you view as scummy, as the town may end up with too many power role claims, making decisions derived setup speculation and Process of Elimination easier.
Sample Role PMs
This part of a role name serves merely to denote that the role is vanilla, and does not add any special powers that would be visible in a role PM.
My Name is Earl is an Open Setup and quintessential example of a Named Townie.