Unclear FAQ Statement regarding the use of OFL in closed source projects

SIL Fonts
1

I am developing a commercial closed source software, that will be using OFL Font Software. In FAQ, question number 1.3 the following is stated:

Question: 1.3 I want to distribute the fonts with my program. Does this mean my program also has to be Free/Libre and Open Source Software?

Answer: No. Only the portions based on the Font Software are required to be released under the OFL. The intent of the license is to allow aggregation or bundling with software under restricted licensing as well.

What is meant by portions based on the Font Software?
Everything that is using the font in my application? Why don’t just write “Only the Font Software is required to…” ?

2

Hi -

Only the parts of your software that are directly derived from the font need to be under the OFL. If all you’ve done is use the font to produce graphic images or UI elements, or use it to render text, then you haven’t modified the font or incorporated it into your source code. (There is a distinction in software between bundling and incorporating/deriving that is best addressed by other web sites.)

The reason we state it that way is to include the case where someone actually modifies the font itself, such as adding symbols, then bundles that modified font.

Hope that helps.