These are custom profile shapes that can be used for the curtain wall frames and caps.
The chair symbol is for 'library part' meaning that these can be used for any objects that can use profiles, which is what curtain walls are made from.
The 'railing' type can be used for profiles used for rails and posts.
Like curtain walls, railings are also made from objects, but they are have there own 'railing' profile type.
In my image you will also see some 'cornice' profiles in the railing settings, because I sometimes use the railing tool to place my cornices (so they are set as 'library part' type as well as 'railing' type and also 'beam' type).
Profiles can be used with more than one type.
One of the forum moderators. Versions 6.5 to 27 Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10 Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11