URW’s version of Helvetica. Differences can be seen in the unusual weight distribution in heavy weights, and in the Bold Extended which is rounder where Neue Helvetica is squared.
Nimbus Sans L is a version spaced to match Linotype’s PostScript version of Helvetica. It was released under the GNU General Public License in 1996, and donated to the Ghostscript. Derivatives include TeX Gyre Heros (GUST, for use in the TeX scientific document preparation software) and FreeSans (2002). [Wikipedia]