T1_SPEC.pdf p.8 に
Type 1 BuildChar begins by using the character code as an index into the Encoding array in the font dictionary to obtain the name of the character to be built. This step is explained in the PostScript Language Reference Manual; among other advantages, it enables a user to re-encode a Type 1 font program by changing the Encoding array without changing anything else.
とか書いてあってもやっとする。PLRM を読めってことか・・・？PostScript Language Reference Third edition まで読みたくないなぁ・・・。p.94 や pp.328-330 や p.773 Appendix E Character Sets and Encoding Vectors に記載はあるんだけど・・・。
