Google Fonts without specified subset in stylesheet - css

Question

Today I ran into a Google Font that's not loaded the usual way, and I'm hoping that someone can clarify this for me.
Why do some Google Fonts not have specified subsets in the stylesheets?
Here's an example of Roboto:
/* cyrillic-ext */
#font-face {
font-family: 'Roboto';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/roboto/v30/KFOmCnqEu92Fr1Mu72xKOzY.woff2) format('woff2');
unicode-range: U+0460-052F, U+1C80-1C88, U+20B4, U+2DE0-2DFF, U+A640-A69F, U+FE2E-FE2F;
}
/* cyrillic */
#font-face {
font-family: 'Roboto';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/roboto/v30/KFOmCnqEu92Fr1Mu5mxKOzY.woff2) format('woff2');
unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}
/* greek-ext */
#font-face {
font-family: 'Roboto';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/roboto/v30/KFOmCnqEu92Fr1Mu7mxKOzY.woff2) format('woff2');
unicode-range: U+1F00-1FFF;
}
/* greek */
#font-face {
font-family: 'Roboto';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/roboto/v30/KFOmCnqEu92Fr1Mu4WxKOzY.woff2) format('woff2');
unicode-range: U+0370-03FF;
}
/* vietnamese */
#font-face {
font-family: 'Roboto';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/roboto/v30/KFOmCnqEu92Fr1Mu7WxKOzY.woff2) format('woff2');
unicode-range: U+0102-0103, U+0110-0111, U+0128-0129, U+0168-0169, U+01A0-01A1, U+01AF-01B0, U+1EA0-1EF9, U+20AB;
}
/* latin-ext */
#font-face {
font-family: 'Roboto';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/roboto/v30/KFOmCnqEu92Fr1Mu7GxKOzY.woff2) format('woff2');
unicode-range: U+0100-024F, U+0259, U+1E00-1EFF, U+2020, U+20A0-20AB, U+20AD-20CF, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* latin */
#font-face {
font-family: 'Roboto';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/roboto/v30/KFOmCnqEu92Fr1Mu4mxK.woff2) format('woff2');
unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
And here's an example of Train One:
Full stylesheet can be found here: https://fonts.googleapis.com/css?family=Train+One
/* [2] */
#font-face {
font-family: 'Train One';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/trainone/v13/gyB-hwkiNtc6KnxUVjWHP87JR5-7NdB589yspgpx0N7r5-25NB8.2.woff2) format('woff2');
unicode-range: U+ffd7, U+ffda-ffdc, U+ffe0-ffe2, U+ffe4, U+ffe6, U+ffe8-ffee, U+1f100-1f10c, U+1f110-1f16c, U+1f170-1f1ac, U+1f200-1f202, U+1f210-1f234;
}
/* [3] */
#font-face {
font-family: 'Train One';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/trainone/v13/gyB-hwkiNtc6KnxUVjWHP87JR5-7NdB589yspgpx0N7r5-25NB8.3.woff2) format('woff2');
unicode-range: U+fa10, U+fa12-fa6d, U+fb00-fb04, U+fe10-fe19, U+fe30-fe42, U+fe44-fe52, U+fe54-fe66, U+fe68-fe6b, U+ff02, U+ff04, U+ff07, U+ff51, U+ff5b, U+ff5d, U+ff5f-ff60, U+ff66, U+ff69, U+ff87, U+ffa1-ffbe, U+ffc2-ffc7, U+ffca-ffcf, U+ffd2-ffd6;
}
/* [5] */
#font-face {
font-family: 'Train One';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/trainone/v13/gyB-hwkiNtc6KnxUVjWHP87JR5-7NdB589yspgpx0N7r5-25NB8.5.woff2) format('woff2');
unicode-range: U+9e8b-9e8c, U+9e8e-9e8f, U+9e91-9e92, U+9e95-9e96, U+9e98, U+9e9b, U+9e9d-9e9e, U+9ea4-9ea5, U+9ea8-9eaa, U+9eac-9eb0, U+9eb3-9eb5, U+9eb8, U+9ebc-9ebf, U+9ec3, U+9ec6, U+9ec8, U+9ecb-9ecd, U+9ecf-9ed1, U+9ed4-9ed5, U+9ed8, U+9edb-9ee0, U+9ee4-9ee5, U+9ee7-9ee8, U+9eec-9ef2, U+9ef4-9ef9, U+9efb-9eff, U+9f02-9f03, U+9f07-9f09, U+9f0e-9f12, U+9f14-9f17, U+9f19-9f1b, U+9f1f-9f22, U+9f26, U+9f2a-9f2c, U+9f2f, U+9f31-9f32, U+9f34, U+9f37, U+9f39-9f3a, U+9f3c-9f3f, U+9f41, U+9f43-9f47, U+9f4a, U+9f4e-9f50, U+9f52-9f58, U+9f5a, U+9f5d-9f61, U+9f63, U+9f66-9f6a, U+9f6c-9f73, U+9f75-9f77, U+9f7a, U+9f7d, U+9f7f, U+9f8f-9f92, U+9f94-9f97, U+9f99, U+9f9c-9fa3, U+9fa5, U+9fb4, U+9fbc-9fc2, U+9fc4, U+9fc6, U+9fcc, U+f900-f92c;
}
/* [6] */
#font-face {
font-family: 'Train One';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/trainone/v13/gyB-hwkiNtc6KnxUVjWHP87JR5-7NdB589yspgpx0N7r5-25NB8.6.woff2) format('woff2');
unicode-range: U+9c3e, U+9c41, U+9c43-9c4a, U+9c4e-9c50, U+9c52-9c54, U+9c56, U+9c58, U+9c5a-9c61, U+9c63, U+9c65, U+9c67-9c6b, U+9c6d-9c6e, U+9c70, U+9c72, U+9c75-9c78, U+9c7a-9c7c, U+9ce6-9ce7, U+9ceb-9cec, U+9cf0, U+9cf2, U+9cf6-9cf7, U+9cf9, U+9d02-9d03, U+9d06-9d09, U+9d0b, U+9d0e, U+9d11-9d12, U+9d15, U+9d17-9d18, U+9d1b-9d1f, U+9d23, U+9d26, U+9d2a-9d2c, U+9d2f-9d30, U+9d32-9d34, U+9d3a, U+9d3c-9d3f, U+9d41-9d48, U+9d4a, U+9d50-9d54, U+9d59, U+9d5d-9d65, U+9d69-9d6c, U+9d6f-9d70, U+9d72-9d73, U+9d76-9d77, U+9d7a-9d7c, U+9d7e, U+9d83-9d84, U+9d86-9d87, U+9d89-9d8a, U+9d8d-9d8e, U+9d92-9d93, U+9d95-9d9a, U+9da1, U+9da4, U+9da9-9dac, U+9dae, U+9db1-9db2, U+9db5, U+9db8-9dbd, U+9dbf-9dc4, U+9dc6-9dc7, U+9dc9-9dca, U+9dcf, U+9dd3-9dd7, U+9dd9-9dda, U+9dde-9de0, U+9de3, U+9de5-9de7, U+9de9, U+9deb, U+9ded-9df0, U+9df3-9df4, U+9df8, U+9dfd-9dfe, U+9e02, U+9e07, U+9e0a, U+9e0d-9e0e, U+9e10-9e12, U+9e15-9e16, U+9e19-9e1f, U+9e75, U+9e79-9e7d, U+9e80-9e85, U+9e87-9e88;
}
/* [7] */
#font-face {
font-family: 'Train One';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/trainone/v13/gyB-hwkiNtc6KnxUVjWHP87JR5-7NdB589yspgpx0N7r5-25NB8.7.woff2) format('woff2');
unicode-range: U+9ae5-9ae7, U+9ae9, U+9aeb-9aec, U+9aee-9aef, U+9af1-9af5, U+9af7, U+9af9-9afb, U+9afd, U+9aff-9b06, U+9b08-9b09, U+9b0b-9b0e, U+9b10, U+9b12, U+9b16, U+9b18-9b1d, U+9b1f-9b20, U+9b22-9b23, U+9b25-9b2f, U+9b32-9b35, U+9b37, U+9b39-9b3b, U+9b3d, U+9b43-9b44, U+9b48, U+9b4b-9b4f, U+9b51, U+9b55-9b58, U+9b5b, U+9b5e, U+9b61, U+9b63, U+9b65-9b66, U+9b68, U+9b6a-9b6f, U+9b72-9b79, U+9b7f-9b80, U+9b83-9b87, U+9b89-9b8b, U+9b8d, U+9b8f-9b94, U+9b96-9b97, U+9b9a, U+9b9d-9ba0, U+9ba6-9ba7, U+9ba9-9baa, U+9bac, U+9bb0-9bb2, U+9bb4, U+9bb7-9bb9, U+9bbb-9bbc, U+9bbe-9bc1, U+9bc6-9bc8, U+9bca, U+9bce-9bd2, U+9bd4, U+9bd7-9bd8, U+9bdd, U+9bdf, U+9be1-9be5, U+9be7, U+9bea-9beb, U+9bee-9bf3, U+9bf5, U+9bf7-9bfa, U+9bfd, U+9bff-9c00, U+9c02, U+9c04, U+9c06, U+9c08-9c0d, U+9c0f-9c16, U+9c18-9c1e, U+9c21-9c2a, U+9c2d-9c32, U+9c35-9c37, U+9c39-9c3a, U+9c3d;
}
/* [8] */
#font-face {
font-family: 'Train One';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/trainone/v13/gyB-hwkiNtc6KnxUVjWHP87JR5-7NdB589yspgpx0N7r5-25NB8.8.woff2) format('woff2');
unicode-range: U+98eb, U+98ed-98ee, U+98f0-98f1, U+98f3, U+98f6, U+9902, U+9907-9909, U+9911-9912, U+9914-9918, U+991a-9922, U+9924, U+9926-9927, U+992b-992c, U+992e, U+9931-9935, U+9939-993e, U+9940-9942, U+9945-9949, U+994b-994e, U+9950-9952, U+9954-9955, U+9958-9959, U+995b-995c, U+995e-9960, U+9963, U+9997-9998, U+999b, U+999d-999f, U+99a3, U+99a5-99a6, U+99a8, U+99ad-99ae, U+99b0-99b2, U+99b5, U+99b9-99ba, U+99bc-99bd, U+99bf, U+99c1, U+99c3, U+99c8-99c9, U+99d1, U+99d3-99d5, U+99d8-99df, U+99e1-99e2, U+99e7, U+99ea-99ee, U+99f0-99f2, U+99f4-99f5, U+99f8-99f9, U+99fb-99fe, U+9a01-9a05, U+9a08, U+9a0a-9a0c, U+9a0f-9a11, U+9a16, U+9a1a, U+9a1e, U+9a20, U+9a22-9a24, U+9a27, U+9a2b, U+9a2d-9a2e, U+9a31, U+9a33, U+9a35-9a38, U+9a3e, U+9a40-9a45, U+9a47, U+9a4a-9a4e, U+9a51-9a52, U+9a54-9a58, U+9a5b, U+9a5d, U+9a5f, U+9a62, U+9a64-9a65, U+9a69-9a6c, U+9aaa, U+9aac-9ab0, U+9ab2, U+9ab4-9ab7, U+9ab9, U+9abb-9ac1, U+9ac3, U+9ac6, U+9ac8, U+9ace-9ad3, U+9ad5-9ad7, U+9adb-9adc, U+9ade-9ae0, U+9ae2-9ae4;
}
/* [9] */
#font-face {
font-family: 'Train One';
font-style: normal;
font-weight: 400;
src: url(https://fonts.gstatic.com/s/trainone/v13/gyB-hwkiNtc6KnxUVjWHP87JR5-7NdB589yspgpx0N7r5-25NB8.9.woff2) format('woff2');
unicode-range: U+971d, U+9721-9724, U+9728, U+972a, U+9730-9731, U+9733, U+9736, U+9738-9739, U+973b, U+973d-973e, U+9741-9744, U+9746-974a, U+974d-974f, U+9751, U+9755, U+9757-9758, U+975a-975c, U+9760-9761, U+9763-9764, U+9766-9768, U+976a-976b, U+976e, U+9771, U+9773, U+9776-977d, U+977f-9781, U+9785-9786, U+9789, U+978b, U+978f-9790, U+9795-9797, U+9799-979a, U+979c, U+979e-97a0, U+97a2-97a3, U+97a6, U+97a8, U+97ab-97ac, U+97ae, U+97b1-97b6, U+97b8-97ba, U+97bc, U+97be-97bf, U+97c1, U+97c3-97ce, U+97d0-97d1, U+97d4, U+97d7-97d9, U+97db-97de, U+97e0-97e1, U+97e4, U+97e6, U+97ed-97ef, U+97f1-97f2, U+97f4-97f8, U+97fa, U+9804, U+9807, U+980a, U+980c-980f, U+9814, U+9816-9817, U+9819-981a, U+981c, U+981e, U+9820-9821, U+9823-9826, U+982b, U+982e-9830, U+9832-9835, U+9837, U+9839, U+983d-983e, U+9844, U+9846-9847, U+984a-984b, U+984f, U+9851-9853, U+9856-9857, U+9859-985b, U+9862-9863, U+9865-9866, U+986a-986c, U+986f-9871, U+9873-9875, U+98aa-98ab, U+98ad-98ae, U+98b0-98b1, U+98b4, U+98b6-98b8, U+98ba-98bc, U+98bf, U+98c2-98c8, U+98cb-98cc, U+98ce, U+98dc, U+98de, U+98e0-98e1, U+98e3, U+98e5-98e7, U+98e9-98ea;
}
/* The list goes on to [117] ... */
Roboto has unicode-ranges with the subset's name commented above each #font-face statement, while Train One seems to have ever expanding unicode-ranges with numbers commented above each #font-face statement. The list goes on till 117, btw.
The reason why I'm curious, is because it seems to load three font files, just to display Latin characters.
Is this just a very inefficiently built stylesheet, or is there a specific reason why the stylesheet is built this way?
BTW. if it isn't clear, this is a question specifically regarding the Google Fonts API and the way it generates stylesheets. I understand what unicode-ranges are used for. I just don't understand what the Google Fonts API is trying to achieve with such a large amount of #font-face statements and unicode-ranges.