Created attachment 533270 [details, diff] Patch that fixes the issue. As the title says, =media-fonts/alegreya-sans-2.008 installs the font files using TrueType format instead of OpenType format. The attached patch remedies this atrocity.
why do you think it should install otf instead ttf? Wouldn't it be better to enable both via USE flag for example?
My view is that the OpenType version should always be preferred over the TrueType version unless there is a particularly compelling reason to the contrary (e.g. if you intend to use it with broken/legacy software which lacks OpenType support). I am all in favour of making this choice through use flags, but last time I made an effort to that effect (bug 406301) it was deemed to add too much complexity.