Variable: sh-ancestor-alist

Alist showing the direct ancestor of various shells.
This is the basis for `sh-feature'. See also `sh-alias-alist'.
By default we have the following three hierarchies:

csh C Shell
jcsh C Shell with Job Control
tcsh TENEX C Shell
itcsh Ian's TENEX C Shell
rc Plan 9 Shell
es Extensible Shell
sh Bourne Shell
ash Almquist Shell
jsh Bourne Shell with Job Control
bash GNU Bourne Again Shell
ksh88 Korn Shell '88
ksh Korn Shell '93
dtksh CDE Desktop Korn Shell
pdksh Public Domain Korn Shell
wksh Window Korn Shell
zsh Z Shell
oash SCO OA (curses) Shell posix IEEE 1003.2 Shell Standard wsh ? Shell